Data Transmission Method, Terminal Device, and Network Device

ABSTRACT

This application provides a data transmission method, a terminal device, and a network device. The method includes: determining, by a terminal device, reference information; and sending, by the terminal device, second channel state information (CSI) based on a comparison result of the reference information and a status parameter, where the second CSI includes all parameters in first CSI or includes some parameters in the first CSI, the first CSI is CSI that needs to be reported and that is configured by a network device for the terminal device, and the status parameter includes at least one of a transmission parameter of uplink data, a parameter in the first CSI, and a transmission parameter of the first CSI. The data transmission method, the terminal device, and the network device in embodiments of this application help improve transmission performance of CSI.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/714,244, filed on Dec. 13, 2019, which is a continuation ofInternational Application No. PCT/CN2018/091683, filed on Jun. 15, 2018which claims priority to Chinese Patent Application No. 201710940769.5,filed on Sep. 30, 2017. All of the afore-mentioned patent applicationsare hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the communications field, and in particular,to a data transmission method, a terminal device, and a network devicein the communications field.

BACKGROUND

Usually, a network device may send a downlink control information(downlink control information. DCI) in an (n-k)^(th) subframe, totrigger aperiodic channel state information (CSI) reporting and/oruplink data transmission of a terminal device, where both n and k arepositive integers, and n is greater than k. The triggered CSI reportingand uplink data transmission are carried in an uplink channel in ann^(th) subframe. Resource allocation (RA) of the uplink channel in then^(th) subframe is completed by a resource allocation field in DCI inthe (n-k)^(th) subframe. If the terminal device transmits no data in then^(th) subframe, the uplink channel may be used to carry only CSI. Ifthe terminal device also needs to transmit uplink data in the n^(th)subframe, a resource of the uplink channel needs to carry both CSI anduplink data. The CSI and the uplink data share a data resource, and aninformation bit quantity of the CSI is related to a rank indication (RI)reported by the terminal device. Therefore, the network device cannotdetermine, during resource allocation, a quantity of resources that theCSI should occupy, and a quantity of resources occupied by the uplinkdata. Therefore, uplink channel resources respectively occupied by theuplink data and the CSI are changing, and are dynamically adjusteddepending on an actual information bit quantity of the CSI.

The CSI fed back by the terminal device to the network device usuallyincludes parameters such as a rank indication (RI), a precoding matrixindicator (PMI), and a channel quality indicator (CQI). An informationbit quantity of the PMI and an information bit quantity of the CQI maychange as the RI changes. Therefore, to ensure that both a maximumquantity of PMI bits and a maximum quantity of CQI bits can be carriedin the uplink channel together with the uplink data, the network devicemay always allocate a resource based on a maximum CSI bit quantity.However, the CSI reporting triggered by the network device may behigh-precision CSI reporting, and bit quantities of high-precision CSImay differ by one time with different RIs. For example, when RI=1, thePMI and/or the CQI are/is approximately 300 bits, and when RI=2, the PMIand/or the CQI are/is close to 600 bits. In this case, if the networkdevice always allocates an uplink channel resource based on a maximumbit quantity (in other words, RI=2), but the terminal device frequentlyreports CSI for which RI=1, the uplink channel resource is wasted.

Therefore, the network device may not allocate a resource based on amaximum CSI bit quantity corresponding to an RI, but estimates, based onprior information, an RI reported by the terminal device. In this case,an uplink channel resource allocated by the network device to theterminal device is unnecessarily capable of satisfying an uplink channelresource needed by CSI reported by the terminal device. How the terminaldevice reports CSI by using a limited uplink channel resource allocatedby the network device to the terminal device has become a problem thatis to be resolved urgently.

SUMMARY

This application provides a data transmission method, a terminal device,and a network device, to help improve transmission performance of CSI.

According to a first aspect, a data transmission method is provided. Themethod includes: determining, by a terminal device, referenceinformation; and sending, by the terminal device, second channel stateinformation (CSI) based on a comparison result of the referenceinformation and a status parameter, where the second CSI includes allparameters in first CSI or includes some parameters in the first CSI,the first CSI is CSI that needs to be reported and that is configured bya network device for the terminal device, and the status parameterincludes at least one of a transmission parameter of uplink data, aparameter in the first CSI, and a transmission parameter of the firstCSI.

Specifically, the terminal device may determine the first CSI that needsto be reported and that is configured by the network device for theterminal device. However, an uplink channel resource configured by thenetwork device for the terminal device may be insufficient. Therefore,in an embodiment of this application, CSI actually reported by theterminal device is the second CSI, and the second CSI includes all orpart of parameters in the first CSI. Before reporting to the networkdevice, the terminal device may first determine the referenceinformation, and determine, based on the reference information, that allparameters in the first CSI need to be reported or some parameters inthe first CSI need to be reported. In other words, the terminal devicecompares the status parameter with the reference information, anddetermines a parameter of the finally reported second CSI based on theobtained comparison result.

It should be understood that, the reference information determined bythe terminal device may be determined by the terminal device based on apredefined rule or may be determined by the terminal device based on aconfiguration of the network device. In other words, the referenceinformation may be predefined, or may be configured by the networkdevice for the terminal device by using signaling. This is not limitedin this embodiment of this application.

In this specification, parameters in the first CSI are parametersincluded in the first CSI, for example, parameters such as an RI, a PMI,and a CQI, and transmission parameters of the first CSI are parametersused to indicate transmission situations of the first CSI, for example,a quantity of resource elements (REs) occupied by the first CSI on anuplink channel, a quantity of modulation symbols of the first CSI, aninformation bit quantity of the first CSI, and a bit quantity of thefirst CSI after channel coding is performed. Likewise, transmissionparameters of the uplink data may be parameters used to indicatetransmission situations of the uplink data, for example, a channelcoding code rate of the uplink data, a quantity of REs occupied by theuplink data on the uplink channel, a quantity of modulation symbols ofthe uplink data, and a ratio of the quantity of REs occupied by theuplink data on the uplink channel to a total quantity of REs included inthe uplink channel.

According to the data transmission method in this embodiment of thisapplication, after determining, based on the reference information andthe CSI that needs to be reported and that is configured by the networkdevice for the terminal device, CSI that can be actually reported, theterminal device reports the CSI, so that the terminal device canproperly use a limited uplink channel resource allocated by the networkdevice to the terminal device, thereby improving transmissionperformance of the CSI.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate at least one of athreshold of the rank indication (RI) and a threshold of a transmissionparameter of the second CSI, where the transmission parameter of thesecond CSI includes at least one of the following parameters: thequantity of resource elements (REs) occupied by the second CSI on theuplink channel, a quantity of modulation symbols of the second CSI, aninformation bit quantity of the second CSI, and a bit quantity of thesecond CSI after channel coding is performed.

It should be understood that, the foregoing indication may be a directindication or may be an indirect indication (which is a correspondingthreshold that can be derived by using a mapping relationship). This isnot limited in this embodiment of this application. For example, for thedirect indication, the reference information may directly be that thethreshold of the RI is 2. For the indirect indication, the referenceinformation may be a threshold identifier of the RI, and the terminaldevice may determine, based on the threshold identifier, that thethreshold of the RI is 2. All these situations shall fall within theprotection scope of the embodiments of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate the threshold ofthe RI, and the status parameter is an RI in the first CSI. If the RI inthe first CSI is greater than the threshold of the RI, the second CSIincludes some parameters in the first CSI, or if the RI in the first CSIis less than or equal to the threshold of the RI, the second CSIincludes all parameters in the first CSI.

It should be understood that, because the second CSI includes allparameters or some parameters in the first CSI, the RI in the first CSIis the same as an RI in the second CSI in this embodiment of thisapplication. It should be further understood that, if the RI in thefirst CSI is equal to the threshold of the RI, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a first thresholdof the quantity of REs occupied by the second CSI on the uplink channel,and the status parameter is a quantity of REs occupied by the first CSIon the uplink channel; and if the quantity of REs occupied by the firstCSI on the uplink channel is greater than the first threshold, thesecond CSI includes some parameters in the first CSI, or if the quantityof REs occupied by the first CSI on the uplink channel is less than orequal to the first threshold, the second CSI includes all parameters inthe first CSI.

It should be understood that, the terminal device may directly determinethe quantity of REs occupied by the first CSI on the uplink channel, ormay calculate, based on the RI in the first CSI, the quantity of REsoccupied by the first CSI on the uplink channel. It should be furtherunderstood that, if the quantity of REs occupied by the first CSI on theuplink channel is equal to the first threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a second thresholdof the quantity of modulation symbols of the second CSI, and the statusparameter is the quantity of modulation symbols of the first CSI; and ifthe quantity of modulation symbols of the first CSI is greater than thesecond threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of modulation symbols of the first CSI is lessthan or equal to the second threshold, the second CSI includes allparameters in the first CSI.

It should be understood that, the terminal device may directly determinethe quantity of modulation symbols of the first CSI, or may calculate,based on the RI in the first CSI, the quantity of modulation symbols ofthe first CSI. It should be further understood that, if the quantity ofmodulation symbols of the first CSI is equal to the second threshold,the second CSI may alternatively include some parameters in the firstCSI. This is not limited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a third thresholdof an information bit quantity of the second CSI, and the statusparameter is an information bit quantity of the first CSI; and if theinformation bit quantity of the first CSI is greater than the thirdthreshold, the second CSI includes some parameters in the first CSI, orif the information bit quantity of the first CSI is less than or equalto the third threshold, the second CSI includes all parameters in thefirst CSI.

It should be understood that, the information bit quantity of the firstCSI is a bit quantity of the first CSI before channel coding isperformed. The terminal device may directly determine the informationbit quantity of the first CSI, or may calculate, based on the RI in thefirst CSI, the information bit quantity of the first CSI. It should befurther understood that, if the information bit quantity of the firstCSI is equal to the third threshold, the second CSI may alternativelyinclude some parameters in the first CSI. This is not limited in thisembodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a fourth thresholdof a bit quantity of the second CSI after channel coding is performed,and the status parameter is a bit quantity of the first CSI afterchannel coding is performed; and if the bit quantity of the first CSIafter channel coding is performed is greater than the fourth threshold,the second CSI includes some parameters in the first CSI, or if the bitquantity of the first CSI after channel coding is performed is less thanor equal to the fourth threshold, the second CSI includes all parametersin the first CSI.

It should be understood that, the terminal device may directly determinethe bit quantity of the first CSI after channel coding is performed, ormay calculate, based on the RI in the first CSI, the bit quantity of thefirst CSI after channel coding is performed. It should be furtherunderstood that, if the bit quantity of the first CSI after channelcoding is performed is equal to the fourth threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the sending, by the terminal device, second CSI includes:sending, by the terminal device, the second CSI and the uplink data,where the uplink data and the second CSI are carried on a same uplinkchannel.

Specifically, the terminal device may add the second CSI to the uplinkchannel together with the uplink data and send the second CSI and theuplink data to the network device. In this case, the uplink channelresource allocated by the network device is shared by the second CSI andthe uplink data.

With reference to the first aspect, in some implementations of the firstaspect, the transmission parameter of the second CSI further includes: aratio of the quantity of REs occupied by the second CSI on the uplinkchannel to a total quantity of REs included in the uplink channel.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a fifth thresholdof the ratio of the quantity of REs occupied by the second CSI on theuplink channel to the total quantity of REs included in the uplinkchannel, and the status parameter is a ratio of a quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel; and if the ratio of the quantity ofREs occupied by the first CSI on the uplink channel to the totalquantity of REs included in the uplink channel is greater than the fifththreshold, the second CSI includes some parameters in the first CSI, orif the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is less than or equal to the fifth threshold, the second CSIincludes all parameters in the first CSI.

It should be understood that, resource elements of the uplink channelmay be collectively referred to as a resource element set, and the ratioof the quantity of REs occupied by the first CSI on the uplink channelto the total quantity of REs included in the uplink channel may also bereferred to as a ratio of a quantity of REs of the first CSI in aresource element set to a total quantity of REs in the resource elementset. This is not limited in this embodiment of this application. Theterminal device may directly determine the ratio of the quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel, or may calculate, based on the RI inthe first CSI, the ratio of the quantity of REs occupied by the firstCSI on the uplink channel to the total quantity of REs included in theuplink channel. It should be further understood that, if the ratio ofthe quantity of REs occupied by the first CSI on the uplink channel tothe total quantity of REs included in the uplink channel is equal to thefifth threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a threshold of thetransmission parameter of the uplink data; and the transmissionparameter of the uplink data includes at least one of the followingparameters: a channel coding code rate of the uplink data, a quantity ofREs occupied by the uplink data on the uplink channel, a quantity ofmodulation symbols of the uplink data, and a ratio of the quantity ofREs occupied by the uplink data on the uplink channel to a totalquantity of REs included in the uplink channel.

It should be understood that, the foregoing indication may be a directindication or may be an indirect indication (which is a correspondingthreshold that can be derived by using a mapping relationship). This isnot limited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a sixth thresholdof the channel coding code rate of the uplink data, and the statusparameter is the channel coding code rate of the uplink data; and if thechannel coding code rate of the uplink data is greater than the sixththreshold, the second CSI includes some parameters in the first CSI, orif the channel coding code rate of the uplink data is less than or equalto the sixth threshold, the second CSI includes all parameters in thefirst CSI.

It should be understood that, the terminal device may calculate thechannel coding code rate of the uplink data based on resource allocationinformation and the parameters in the first CSI. It should be furtherunderstood that, if the channel coding code rate of the uplink data isequal to the sixth threshold, the second CSI may alternatively includesome parameters in the first CSI. This is not limited in this embodimentof this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a sevenththreshold of the quantity of REs occupied by the uplink data on theuplink channel, and the status parameter is the quantity of REs occupiedby the uplink data on the uplink channel; and if the quantity of REsoccupied by the uplink data on the uplink channel is less than theseventh threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the uplink data on the uplinkchannel is greater than or equal to the seventh threshold, the secondCSI includes all parameters in the first CSI.

It should be understood that, the terminal device may calculate, basedon the resource allocation information and the parameters in the firstCSI, the quantity of REs occupied by the uplink data on the uplinkchannel. It should be further understood that, if the quantity of REsoccupied by the uplink data on the uplink channel is equal to theseventh threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate an eighththreshold of the quantity of modulation symbols of the uplink data, andthe status parameter is the quantity of modulation symbols of the uplinkdata; and if the quantity of modulation symbols of the uplink data isless than the eighth threshold, the second CSI includes some parametersin the first CSI, or if the quantity of modulation symbols of the uplinkdata is greater than or equal to the eighth threshold, the second CSIincludes all parameters in the first CSI.

It should be understood that, the terminal device may calculate thequantity of modulation symbols of the uplink data based on the resourceallocation information and the parameters in the first CSI. It should befurther understood that, if the quantity of modulation symbols of theuplink data is equal to the eighth threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is used to indicate a ninth thresholdof the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel, and the status parameter is the ratio of the quantity of REsoccupied by the uplink data on the uplink channel to the total quantityof REs included in the uplink channel; and if the ratio of the quantityof REs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel is less than the ninththreshold, the second CSI includes some parameters in the first CSI, orif the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel is greater than or equal to the ninth threshold, the second CSIincludes all parameters in the first CSI.

It should be understood that, the terminal device may calculate, basedon the resource allocation information and the parameters in the firstCSI, the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel. It should be further understood that, if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is equal to theninth threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application. It should be further understood that, the referenceinformation may indicate one or more thresholds.

With reference to the first aspect, in some implementations of the firstaspect, before the sending, by the terminal device, second CSI, themethod further includes: determining, by the terminal device based onthe comparison result and priority information, whether to send theuplink data, where the priority information is used to indicatepriorities of the second CSI and the uplink data, and the sending, bythe terminal device, second CSI includes: sending, by the terminaldevice, the second CSI and the uplink data if the terminal devicedetermines to send the uplink data.

Specifically, the terminal device may first determine priorities of CSIand the uplink data based on the priority information, and thendetermine whether the uplink data needs to be sent, in other words,determine, based on the priority information, to preferably discard someinformation in the first CSI or preferably discard the uplink data. Itshould be understood that, the priority information may be predefined,or may be configured by the network device for the terminal device byusing signaling. This is not limited in this embodiment of thisapplication.

With reference to the first aspect, in some implementations of the firstaspect, the parameter in the first CSI includes: second frequency domaingranularity parameters of M subbands and a first frequency domaingranularity parameter, where the first frequency domain granularityparameter includes an RI, and the second frequency domain granularityparameters of the M subbands include a channel quality indicator (CQI)of each of the M subbands and/or a precoding matrix indicator (PMI) ofthe subband; and a parameter in the second CSI includes any one of thefollowing: second frequency domain granularity parameters of N subbandsand the first frequency domain granularity parameter; all or part ofsecond frequency domain granularity parameters of each of the M subbandsand the first frequency domain granularity parameter; and the firstfrequency domain granularity parameter, the CQI of each of the Msubbands, and a PMI of each of the N subbands, where the M subbandsinclude the N subbands, both M and N are integers greater than or equalto 1, and M is greater than N.

It should be understood that, the first frequency domain granularityparameter is also referred to as a broadband parameter and has a samevalue on the M subbands, and the second frequency domain granularityparameter is also referred to as a subband parameter and has a differentvalue for each of the M subbands. Specifically, if the second CSIreported by the terminal device includes some parameters in the firstCSI, the terminal device may select some parameters in the first CSIbased on a predefined rule to perform reporting. For example, theterminal device may report only a proportion of parameters (for example,an RI, a broadband PMI, all subband CQIs, and a proportion of subbandPMIs; an RI, a broadband PMI, and a proportion of subband PMIs andsubband CQIs; an RI, a broadband PMI, a broadband CQI, a subband PMIand/or a subband CQI of the M subbands whose indexes are the highest; oran RI, and PMIs and/or CQIs corresponding to some DFT vectors) in thefirst CSI based on a default rule.

With reference to the first aspect, in some implementations of the firstaspect, the reference information is predefined, or the referenceinformation is configured by the network device for the terminal deviceby using signaling.

With reference to the first aspect, in some implementations of the firstaspect, the signaling is any one of the following signaling: radioresource control (RRC) signaling, downlink control information (DCI)signaling, and a Media Access Control control element (MAC CE)signaling.

It should be understood that, using the RRC signaling to configure thereference information is applicable to a scenario in which theconfiguration of the reference information does not frequently changeand is relatively stable, and bit overheads of signaling of a physicallayer and a MAC layer may be greatly reduced. Using the DCI signaling toconfigure the reference information helps the terminal device performfast detection, to ensure that the terminal device receives thereference information in a timely manner. However, using the MAC CEsignaling to configure the reference information is applicable to ascenario in which the reference information changes relativelydynamically. A decoding speed of the MAC CE signaling is higher thanthat of the RRC signaling. Therefore, in such a scenario, the networkdevice uses the MAC CE signaling to configure the reference informationmore efficiently.

According to a second aspect, another data transmission method isprovided. The method includes: receiving, by a network device, a rankindication (RI) in second channel state information (CSI); anddetermining, by the network device based on a comparison result obtainedby comparing a status parameter with reference information, at least oneof a bit quantity of the second CSI and a quantity of resource elements(REs) occupied by the second CSI on an uplink channel, where the statusparameter is determined based on the RI, the status parameter includesat least one of a transmission parameter of uplink data, a parameter infirst CSI, and a transmission parameter of the first CSI, the first CSIis CSI that needs to be reported and that is configured by the networkdevice for a terminal device, and the second CSI includes all parametersin the first CSI or includes some parameters in the first CSI.

According to the data transmission method in this embodiment of thisapplication, after determining, based on the reference information andthe CSI that needs to be reported and that is configured by the networkdevice for the terminal device, CSI that can be actually reported, theterminal device reports the CSI, so that the terminal device canproperly use a limited uplink channel resource allocated by the networkdevice to the terminal device, thereby improving transmissionperformance of the CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate at leastone of a threshold of the rank indication (RI) of the second CSI and athreshold of a transmission parameter of the second CSI, where thetransmission parameter of the second CSI includes at least one of thefollowing parameters: the quantity of resource elements (REs) occupiedby the second CSI on the uplink channel, a quantity of modulationsymbols of the second CSI, an information bit quantity of the secondCSI, and a bit quantity of the second CSI after channel coding isperformed.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate thethreshold of the RI, and the status parameter is the RI; and if the RIis greater than the threshold of the RI, the second CSI includes someparameters in the first CSI; or if the RI is less than or equal to thethreshold of the RI, the second CSI includes all parameters in the firstCSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a firstthreshold of the quantity of REs occupied by the second CSI on theuplink channel, and the status parameter is a quantity of REs occupiedby the first CSI on the uplink channel; and if the quantity of REsoccupied by the first CSI on the uplink channel is greater than thefirst threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the first CSI on the uplinkchannel is less than or equal to the first threshold, the second CSIincludes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a secondthreshold of the quantity of modulation symbols of the second CSI, andthe status parameter is the quantity of modulation symbols of the firstCSI; and if the quantity of modulation symbols of the first CSI isgreater than the second threshold, the second CSI includes someparameters in the first CSI, or if the quantity of modulation symbols ofthe first CSI is less than or equal to the second threshold, the secondCSI includes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a thirdthreshold of an information bit quantity of the second CSI, and thestatus parameter is an information bit quantity of the first CSI; and ifthe information bit quantity of the first CSI is greater than the thirdthreshold, the second CSI includes some parameters in the first CSI, orif the information bit quantity of the first CSI is less than or equalto the third threshold, the second CSI includes all parameters in thefirst CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a fourththreshold of a bit quantity of the second CSI after channel coding isperformed, and the status parameter is a bit quantity of the first CSIafter channel coding is performed, and if the bit quantity of the firstCSI after channel coding is performed is greater than the fourththreshold, the second CSI includes some parameters in the first CSI, orif the bit quantity of the first CSI after channel coding is performedis less than or equal to the fourth threshold, the second CSI includesall parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the receiving, by a network device, a rank indication(RI) in second CSI includes: receiving, by the network device, thesecond CSI and the uplink data, where the uplink data and the second CSIare carried on a same uplink channel.

With reference to the second aspect, in some implementations of thesecond aspect, the transmission parameter of the second CSI furtherincludes: a ratio of the quantity of REs occupied by the second CSI onthe uplink channel to a total quantity of REs included in the uplinkchannel.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a fifththreshold of the ratio of the quantity of REs occupied by the second CSIon the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is a ratio of a quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel; and if the ratio of the quantity ofREs occupied by the first CSI on the uplink channel to the totalquantity of REs included in the uplink channel is greater than the fifththreshold, the second CSI includes some parameters in the first CSI, orif the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is less than or equal to the fifth threshold, the second CSIincludes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a thresholdof the transmission parameter of the uplink data; and the transmissionparameter of the uplink data includes at least one of the followingparameters: a channel coding code rate of the uplink data, a quantity ofREs occupied by the uplink data on the uplink channel, a quantity ofmodulation symbols of the uplink data, and a ratio of the quantity ofREs occupied by the uplink data on the uplink channel to a totalquantity of REs included in the uplink channel.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a sixththreshold of the channel coding code rate of the uplink data, and thestatus parameter is the channel coding code rate of the uplink data; andif the channel coding code rate of the uplink data is greater than thesixth threshold, the second CSI includes some parameters in the firstCSI, or if the channel coding code rate of the uplink data is less thanor equal to the sixth threshold, the second CSI includes all parametersin the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a sevenththreshold of the quantity of REs occupied by the uplink data on theuplink channel, and the status parameter is the quantity of REs occupiedby the uplink data on the uplink channel; and if the quantity of REsoccupied by the uplink data on the uplink channel is less than theseventh threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the uplink data on the uplinkchannel is greater than or equal to the seventh threshold, the secondCSI includes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate an eighththreshold of the quantity of modulation symbols of the uplink data, andthe status parameter is the quantity of modulation symbols of the uplinkdata; and if the quantity of modulation symbols of the uplink data isless than the eighth threshold, the second CSI includes some parametersin the first CSI, or if the quantity of modulation symbols of the uplinkdata is greater than or equal to the eighth threshold, the second CSIincludes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is used to indicate a ninththreshold of the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is the ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel; and if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is less than theninth threshold, the second CSI includes some parameters in the firstCSI, or if the ratio of the quantity of REs occupied by the uplink dataon the uplink channel to the total quantity of REs included in theuplink channel is greater than or equal to the ninth threshold, thesecond CSI includes all parameters in the first CSI.

With reference to the second aspect, in some implementations of thesecond aspect, the parameter in the first CSI includes: second frequencydomain granularity parameters of M subbands and a first frequency domaingranularity parameter, where the first frequency domain granularityparameter includes an RI, and the second frequency domain granularityparameters of the M subbands include a channel quality indicator (CQI)of each of the M subbands and/or a precoding matrix indicator (PMI) ofthe subband; and a parameter in the second CSI includes any one of thefollowing: second frequency domain granularity parameters of N subbandsand the first frequency domain granularity parameter; all or part ofsecond frequency domain granularity parameters of each of the M subbandsand the first frequency domain granularity parameter; and the firstfrequency domain granularity parameter, the CQI of each of the Msubbands, and a PMI of each of the N subbands, where the M subbandsinclude the N subbands, both M and N are integers greater than or equalto 1, and M is greater than N.

With reference to the second aspect, in some implementations of thesecond aspect, the reference information is predefined, or the methodfurther includes: sending, by the network device, the referenceinformation to the terminal device by using signaling.

With reference to the second aspect, in some implementations of thesecond aspect, the signaling is any one of the following signaling:radio resource control RRC signaling, downlink control information (DCI)signaling, and a Media Access Control control element (MAC CE)signaling.

According to a third aspect, a terminal device is provided. The terminaldevice is configured to perform the method according to the first aspector any possible implementation of the first aspect. Specifically, theterminal device includes a unit configured to perform the methodaccording to the first aspect or any possible implementation of thefirst aspect.

According to a fourth aspect, a network device is provided. The networkdevice is configured to perform the method according to the secondaspect or any possible implementation of the second aspect.Specifically, the network device includes a unit configured to performthe method according to the second aspect or any possible implementationof the second aspect.

According to a fifth aspect, a terminal device is provided. The terminaldevice includes: a transceiver, a memory, and a processor. Thetransceiver, the memory, and the processor communicate with each otherby using an internal connection path, the memory is configured to storean instruction, the processor is configured to execute the instructionstored in the memory, so as to control a receiver to receive a signaland control a transmitter to send a signal, and when the processorexecutes the instruction stored in the memory, the execution enables theprocessor to perform the method according to the first aspect or anypossible implementation of the first aspect.

According to a sixth aspect, a network device is provided. The networkdevice includes: a transceiver, a memory, and a processor. Thetransceiver, the memory, and the processor communicate with each otherby using an internal connection path, the memory is configured to storean instruction, the processor is configured to execute the instructionstored in the memory, so as to control a receiver to receive a signaland control a transmitter to send a signal, and when the processorexecutes the instruction stored in the memory, the execution enables theprocessor to perform the method according to the second aspect or anypossible implementation of the second aspect.

According to a seventh aspect, a data transmission system is provided.The system includes the terminal device according to the third aspect orany possible implementation of the third aspect and the network deviceaccording to the fourth aspect or any possible implementation of thefourth aspect; or

the system includes the terminal device according to the fifth aspect orany possible implementation of the fifth aspect and the network deviceaccording to the sixth aspect or any possible implementation of thesixth aspect.

According to an eighth aspect, a computer program product is provided.The computer program product includes computer program code, and whenthe computer program code is run by a network device, the network deviceperforms the method according to the first aspect or any possibleimplementation of the first aspect.

According to a ninth aspect, a computer program product is provided. Thecomputer program product includes computer program code, and when thecomputer program code is run by a terminal device, the terminal deviceperforms the method according to the second aspect or any possibleimplementation of the second aspect.

According to a tenth aspect, a chip is provided. The chip includes: aninput interface, an output interface, and at least one processor, andoptionally may further include a memory. The input interface, the outputinterface, the processor, and the memory are connected to each other byusing an internal connection path, the processor and the memory may beconnected to each other by using the internal connection path or anexternal path, the processor is configured to execute code in thememory, and when the code is executed, the processor is configured toperform the method according to the first aspect or any possibleimplementation of the first aspect.

According to an eleventh aspect, a chip is provided. The chip includes:an input interface, an output interface, and at least one processor, andoptionally may further include a memory. The input interface, the outputinterface, the processor, and the memory are connected to each other byusing an internal connection path, the processor and the memory may beconnected to each other by using the internal connection path or anexternal path, the processor is configured to execute code in thememory, and when the code is executed, the processor is configured toperform the method according to the second aspect or any possibleimplementation of the second aspect.

According to a twelfth aspect, a processing apparatus is provided. Theprocessing apparatus includes: a memory; and a processor, configured toread an instruction stored in the memory, to perform any one of theforegoing methods, where steps related to transmission and receivingshould be understood as being performed by the processor by using atransceiver.

The memory may be a non-transitory memory such as a read-only memory(ROM). The memory and the processor may be integrated on a same chip, ormay be separately disposed on different chips. A type of the memory anda manner of disposing the memory and the processor are not limited inthis embodiment of this application.

According to a thirteenth aspect, a computer readable medium isprovided. The computer readable medium is configured to store a computerprogram, where the computer program includes an instruction used toperform the method according to the first aspect or any possibleimplementation of the first aspect.

According to a fourteenth aspect, a computer readable medium isprovided. The computer readable medium is configured to store a computerprogram, where the computer program includes an instruction used toperform the method according to the second aspect or any possibleimplementation of the second aspect.

The computer readable storage medium is non-transitory.

According to a fifteenth aspect, a computer program product including aninstruction is provided. When the computer program product runs on acomputer, the computer performs any one of the foregoing methods.

According to the data transmission method, the terminal device, and thenetwork device in the embodiments of this application, afterdetermining, based on the reference information and the CSI that needsto be reported and that is configured by the network device for theterminal device, the CSI that can be actually reported, the terminaldevice reports the CSI, so that the terminal device can properly use thelimited uplink channel resource allocated by the network device to theterminal device, thereby improving the transmission performance of theCSI.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a communications system according to anembodiment of this application:

FIG. 2 is a schematic flowchart of a data transmission method accordingto an embodiment of this application;

FIG. 3 is a schematic block diagram of a terminal device according to anembodiment of this application;

FIG. 4 is a schematic block diagram of a network device according to anembodiment of this application;

FIG. 5 is a schematic block diagram of another network device accordingto an embodiment of this application; and

FIG. 6 is a schematic block diagram of another terminal device accordingto an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes technical solutions of this application withreference to the accompanying drawings.

A next-generation wireless communications system that is currently at aresearch and development stage may also be referred to as a new radio(NR) system or a future 5th generation (5G) system. Latest researchprogress of a next-generation wireless communications standard indicatesthat, CSI may be sent from a receive end device to a transmit end deviceby using a physical uplink shared channel (PUSCH). A person skilled inthe art should understand that, compared with a physical uplink controlchannel (PUCCH) mainly used to transmit control information, the PUSCHis mainly used to transmit data. Therefore, when transmitting CSI, thePUSCH may further transmit data or may not transmit data. For example, aPUSCH in an uplink subframe may transmit both CSI and data or maytransmit only CSI but not transmit data. The CSI is usually included inuplink control information (UCI), and the UCI is transmitted by usingthe PUSCH.

A frequency band in the embodiments of this application may be referredto as carrier bandwidth, and may be considered as a broadband thatfurther includes at least one bandwidth part. Each bandwidth partincludes at least one contiguous subband, and each subband furtherincludes a plurality of contiguous subcarriers.

Each bandwidth part may correspond to a group of system parameters(numerology), including, for example, but not limited to, a subcarrierspacing and a cyclic prefix (CP), and different bandwidth parts maycorrespond to different system parameters. Optionally, within a sametransmission time interval (TTI), among a plurality of bandwidth parts,only one bandwidth part may be available, and other bandwidth parts arenot available.

During CSI reporting, some or all subbands of a bandwidth part may beallocated and used as a CSI reporting bandwidth, so as to report CSIcorresponding to the CSI reporting bandwidth. It is not difficult tounderstand that, the reporting bandwidth is a segment of bandwidth, theCSI corresponding to the bandwidth needs to be reported, and thebandwidth includes a plurality of subbands. The reporting bandwidthcarries a reference signal that is used to perform channel sounding andthat is sent by a transmit end device, for example, but not limited to,a cell-specific reference signal (CRS), a channel stateinformation-reference signal (CSI-RS), or a demodulation referencesignal (DMRS). Related technical content of the reference signal belongsto the prior art, and is not limited in the embodiments of thisapplication. A receive end device may measure the reference signal, toobtain corresponding CSI.

During CSI reporting, CSI of the entire reporting bandwidth, namely,broadband CSI of the reporting bandwidth, may be reported, or CSI of atleast one subband within the reporting bandwidth may be reported.Alternatively, the foregoing two reporting manners may be combined andused, or another reporting manner is used. For example, the reportingbandwidth includes a plurality of contiguous subbands. However, duringspecific implementation, subbands included in the reporting bandwidthmay be not contiguous. For example, for six contiguous subbands in abandwidth part: a subband 1 to a subband 6, the reporting bandwidth mayinclude the subband 1, the subband 2, the subband 4, and the subband 6.During specific implementation, a frequency band may also be divided inanother manner or based on a hierarchy. For example, in differentdivision manners, quantities of subcarriers included in a subband may bedifferent. A specific manner of dividing a frequency band is not limitedin the embodiments of this application.

As described above, when channel sounding is performed, the receive enddevice obtains channel state information based on the reference signal(RS) transmitted by the transmit end device, and feeds back the obtainedCSI to the transmit end device. The transmit end device may process ato-be-transmitted signal based on the CSI, and send a processedto-be-transmitted signal to the receive end device. During specificimplementation, the CSI may further include, for example, but is notlimited to, at least one of the following information: a channel qualityindicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resourceindicator (CRI), and a rank indication (RI). When processing theto-be-transmitted signal, the transmit end device may directly processthe to-be-transmitted signal by using the CSI fed back by the receiveend device, or may adjust the CSI fed back by the receive end device,and process the to-be-transmitted signal by using adjusted CSI. Forexample, during specific implementation, the transmit end device mayreduce the RI fed back by the receive end device, and process theto-be-transmitted signal by using a reduced RI. For another example, thetransmit end device may further reconstruct a precoding matrixcorresponding to the PMI fed back by the receive end device, and processthe to-be-transmitted signal by using a reconstructed PMI, where thereconstruction process may be, for example, but is not limited to,performing orthogonalization processing on precoding matricescorresponding to PMIs fed back by a plurality of receive end devicesscheduled simultaneously. A method for scheduling a plurality of receiveend devices simultaneously to perform data transmission is also referredto as a multi-user multiple-input multiple-output (multi-usermultiple-input multiple-output (MIMO), MU-MIMO) technology. For anotherexample, the transmit end device may further reduce the CQI fed back bythe receive end device, and process the to-be-transmitted signal byusing a reduced CQI. It should be noted that, if the transmit end deviceadjusts the CSI fed back by the receive end device, the transmit enddevice may need to notify, the receive end device of the adjusted CSI,so that the receive end device restores the to-be-transmitted signalfrom a received signal based on the adjusted CSI. For example, if a basestation adjusts the RI or the CQI, the base station needs to notify thereceive end device of an adjusted RI or CQI. During specificimplementation, a specific manner of adjusting, by the transmit enddevice, the CSI fed back by the receive end device is not limited in theembodiments of this application.

It should be understood that, the technical solutions of the embodimentsof this application may be applied to various communications systems,such as a Global System for Mobile Communications (GSM) system, a CodeDivision Multiple Access (CDMA) system, a Wideband Code DivisionMultiple Access (WCDMA) system, a general packet radio service (GPRS), aLong Term Evolution (LTE) system, an LTE frequency division duplex (FDD)system, an LTE time division duplex (TDD) system. Universal MobileTelecommunications System (UMTS), a worldwide interoperability formicrowave access (WiMAX) communications system, a future 5th generation(5G) system, or a new radio (NR) system.

It should be further understood that, the technical solutions of theembodiments of this application may be further applied to variouscommunications systems based on a non-orthogonal multiple accesstechnology, for example, a sparse code multiple access (SCMA) system.Certainly, SCMA may also be referred to as another name in thecommunications field. Further, the technical solutions of theembodiments of this application may be applied to a multi-carriertransmission system in which the non-orthogonal multiple accesstechnology is used, for example, an orthogonal frequency divisionmultiplexing (OFDM) system, a filter bank multi-carrier (FBMC) system, ageneralized frequency division multiplexing (GFDM) system, or afiltered-orthogonal frequency division multiplexing (F-OFDM) system inwhich the non-orthogonal multiple access technology is used.

It should be further understood that, a terminal device in theembodiments of this application may communicate with one or more corenetworks by using a radio access network (RAN), and the terminal devicemay be referred to as an access terminal, user equipment (UE), asubscriber unit, a subscriber station, a mobile station, a mobileconsole, a remote station, a remote terminal, a mobile device, a userterminal, a terminal, a wireless communications device, a user agent, ora user apparatus. The access terminal may be a cellular phone, acordless phone, a Session Initiation Protocol (SIP) phone, a wirelesslocal loop (WLL) station, a personal digital assistant (PDA), a handhelddevice having a wireless communication function, a computing device,another processing device connected to a wireless modem, an in-vehicledevice, a wearable device, a terminal device in a future 5G network, aterminal device in a future evolved public land mobile network (PLMN),or the like.

It should be further understood that, in the embodiments of thisapplication, a network device may be configured to communicate with aterminal device. The network device may be a base transceiver station(BTS) in a GSM system or a CDMA system, may be a NodeB (NB) in a WCDMAsystem, or may be an evolved NodeB (eNB or eNodeB) in an LTE system.Alternatively, the network device may be a relay station, an accesspoint, an in-vehicle device, a wearable device, a network-side device ina future 5G network, a network device in a future evolved PLMN, or thelike.

The embodiments of this application may be applicable to an LTE systemand a subsequent evolved system such as 5G, or other wirelesscommunications systems in which various wireless access technologies areused, for example, a system in which an access technology such as codedivision multiple access, frequency division multiple access, timedivision multiple access, orthogonal frequency division multiple access,or single-carrier frequency division multiple access is used, and areparticularly applicable to a scenario that requires channel informationfeedback and/or a scenario to which a secondary precoding technology isapplied, for example, a wireless network to which a Massive MIMOtechnology is applied, or a wireless network to which a distributedantenna technology is applied.

It should be understood that, a multiple-input multiple-output (MIMO)technology is that a transmit end device and a receive end devicerespectively use a plurality of transmit antennas and receive antennas,so that a signal is transmitted and received by using the plurality ofantennas of the transmit end device and the receive end device, therebyimproving communication quality. The multiple-input multiple-outputtechnology can fully use a space resource and implement multiple-inputmultiple-output by using the plurality of antennas, and can multiply asystem channel capacity without an increase in spectrum resources andantenna transmit power.

MIMO may be divided into single-user multiple-input multiple-output(single-user MIMO, SU-MIMO) and multi-user multiple-inputmultiple-output (multi-user MIMO, MU-MIMO). In Massive MIMO, based on amulti-user beamforming principle, hundreds of antennas are arranged at atransmit end device, to modulate respective beams for dozens of targetreceivers, and dozens of signals are transmitted simultaneously on asame frequency resource by performing space signal isolation. Therefore,the Massive MIMO technology can fully use a spatial degree of freedombrought by a large-scale antenna configuration, to improve spectralefficiency.

FIG. 1 is a schematic diagram of a communications system used in anembodiment of this application. As shown in FIG. 1 , the communicationssystem 100 includes a network device 102, and the network device 102 mayinclude a plurality of antenna groups. Each antenna group may includeone or more antennas. For example, an antenna group may include antennas104 and 106, another antenna group may include antennas 108 and 110, andan additional group may include antennas 112 and 114. For each antennagroup, two antennas are shown in FIG. 1 . However, more or fewerantennas may be used for each group. The network device 102 mayadditionally include a transmitter chain and a receiver chain. A personof ordinary skill in the art may understand that the transmitter chainand the receiver chain may both include a plurality of componentsrelated to signal sending and receiving, for example, a processor, amodulator, a multiplexer, a demodulator, a demultiplexer, or an antenna.

The network device 102 may communicate with a plurality of terminaldevices. For example, the network device 102 may communicate with aterminal device 116 and a terminal device 122. However, it may beunderstood that the network device 102 may communicate with any quantityof terminal devices similar to the terminal device 116 or 122. Theterminal devices 116 and 122 each may be, for example, a cellular phone,a smartphone, a portable computer, a handheld communications device, ahandheld computing device, a satellite radio apparatus, a globalpositioning system, a PDA, and/or any other suitable device configuredto perform communication in the wireless communications system 100.

As shown in FIG. 1 , the terminal device 116 communicates with theantennas 112 and 114, where the antennas 112 and 114 send information tothe terminal device 116 by using a forward link 118, and receiveinformation from the terminal device 116 by using a backward link 120.Moreover, the terminal device 122 communicates with the antennas 104 and106, where the antennas 104 and 106 send information to the terminaldevice 122 by using a forward link 124, and receive information from theterminal device 122 by using a backward link 126.

For example, in a frequency division duplex FDD system, the forward link118 may use a frequency band different from that used by the backwardlink 120, and the forward link 124 may use a frequency band differentfrom that used by the backward link 126.

For another example, in a time division duplex TDD system and a fullduplex system, the forward link 118 and the backward link 120 may use acommon frequency band, and the forward link 124 and the backward link126 may use a common frequency band.

Each group of antennas and/or an area designed for communication isreferred to as a sector of the network device 102. For example, anantenna group may be designed to communicate with a terminal device in asector within a coverage area of the network device 102. When thenetwork device 102 communicates with the terminal devices 116 and 122 byrespectively using the forward links 118 and 124, transmit antennas ofthe network device 102 may improve signal-to-noise ratios of the forwardlinks 118 and 124 by performing beamforming. In addition, compared witha manner in which the network device sends a signal to all terminaldevices served by the network device by using a single antenna, when thenetwork device 102 sends, by performing beamforming, a signal to theterminal devices 116 and 122 that are randomly distributed in a relatedcoverage area, less interference is caused to a mobile device in aneighboring cell.

In a given time, the network device 102, the terminal device 116, or theterminal device 122 may be a wireless communications sending apparatusand/or a wireless communications receiving apparatus. When sending data,the wireless communications sending apparatus may encode the data fortransmission. Specifically, the wireless communications sendingapparatus may obtain a particular quantity of data bits to be sent to awireless communications receiving apparatus by using a channel. Forexample, the wireless communications sending apparatus may generate,receive from another communications apparatus, or store in a memory, theparticular quantity of data bits to be sent to the wirelesscommunications receiving apparatus by using the channel. Such data bitsmay be included in one or more transport blocks of data, and thetransport block may be segmented to generate a plurality of code blocks.

Moreover, the communications system 100 may be a public land mobilenetwork PLMN, a device to device (D2D) network, a machine to machine(M2M) network, or another network. FIG. 1 is only an example of asimplified schematic diagram for convenience of understanding, and thenetwork may further include another network device that is not drawn inFIG. 1 .

FIG. 2 is a schematic flowchart of a data transmission method 200according to an embodiment of this application. The method 200 may beapplied to the communications system 100 shown in FIG. 1 , but thisembodiment of this application is not limited thereto.

S210. A terminal device determines reference information.

S220. The terminal device sends second channel state information (CSI)based on a comparison result of the reference information and a statusparameter, where the second CSI includes all parameters in first CSI orincludes some parameters in the first CSI, the first CSI is CSI thatneeds to be reported and that is configured by a network device for theterminal device, and the status parameter includes at least one of atransmission parameter of uplink data, a parameter in the first CSI, anda transmission parameter of the first CSI.

S230. The network device receives the second CSI sent by the terminaldevice, determines the status parameter based on an RI in the secondCSI, and determines, based on the comparison result obtained bycomparing the status parameter with the reference information, at leastone of a bit quantity of the second CSI and a quantity of resourceelements (Res) occupied by the second CSI on an uplink channel.

Specifically, the terminal device needs to report the first CSI based ona configuration of the network device. It should be understood that, thefirst CSI is CSI obtained by the terminal device by measuring areference signal. However, actually, an uplink channel resourceconfigured by the network device for the terminal device may beinsufficient. Therefore, in this embodiment of this application, theterminal device may choose to actually report all or part of parametersin the first CSI. In other words, actually reported CSI is the secondCSI, and the second CSI includes all or part of parameters in the firstCSI. Whether all parameters in the first CSI or some parameters in thefirst CSI specifically need to be reported may be determined by theterminal device based on the reference information. In other words, theterminal device compares the status parameter with the referenceinformation, and determines a parameter of the finally reported secondCSI based on the obtained comparison result. It should be understoodthat, the first CSI and the second CSI are only for convenience of briefdescription. During actual implementation, CSI obtained by the terminaldevice through measurement is referred to as the first CSI, and CSIreported by the terminal device is referred to as the second CSI. Whenall of the CSI obtained through measurement needs to be reported, thesecond CSI is actually the first CSI.

It should be understood that, the reference information may bedetermined by the terminal device based on a predefined rule or may bedetermined by the terminal device based on the configuration of thenetwork device. In other words, the reference information may bepredefined, or may be configured by the network device for the terminaldevice by using signaling. This is not limited in this embodiment ofthis application.

The first CSI, namely, the CSI that needs to be reported and that isconfigured by the network device for the terminal device, is explainedand described in detail below. It is assumed that communicationbandwidth of the terminal device and the network device includes Msubbands, where M is an integer greater than or equal to 1. Each of theM subbands includes a plurality of physical resource blocks (PRB), whereeach of the plurality of PRBs includes a plurality of resource elements(r RE). After measuring a reference signal such as a channel stateinformation-reference signal (CSI-RS), the terminal device may obtainthe first CSI. The first CSI may include an RI and a CQI, or the firstCSI may include an RI, a CQI, and a PMI, and may further include anotherparameter. This is not limited in this embodiment of this application.

It should be understood that, when the terminal device reports thesecond CSI, the status parameter may include at least one of theparameter in the first CSI and the transmission parameter of the firstCSI, or when the terminal device reports both the second CSI and theuplink data, the status parameter may further include the transmissionparameter of the uplink data. This is not limited in this embodiment ofthis application.

In this specification, parameters in the first CSI are parametersincluded in the first CSI, for example, parameters such as an RI, a PMI,and a CQI, and transmission parameters of the first CSI are parametersused to indicate transmission situations of the first CSI, for example,a quantity of resource elements (REs) occupied by the first CSI on anuplink channel, a quantity of modulation symbols of the first CSI, aninformation bit quantity of the first CSI, and a bit quantity of thefirst CSI after channel coding is performed. Likewise, transmissionparameters of the uplink data may be parameters used to indicatetransmission situations of the uplink data, for example, a channelcoding code rate of the uplink data, a quantity of REs occupied by theuplink data on the uplink channel, a quantity of modulation symbols ofthe uplink data, and a ratio of the quantity of REs occupied by theuplink data on the uplink channel to a total quantity of REs included inthe uplink channel.

Therefore, the status parameter may be any one or more parameters in theforegoing example. When the status parameter includes one parameter, thereference information may be a threshold corresponding to the parameteror may be a plurality of thresholds corresponding to the parameter. Whenthe status parameter includes a plurality of parameters, the referenceinformation may be a threshold corresponding to each of the plurality ofparameters. This is not limited in this embodiment of this application.

In this embodiment of this application, the terminal device may convert,based on the reference information, an existing parameter into aparameter that has a same property and that is indicated by thereference information, and then perform comparison, or may convert,based on the status parameter, a parameter indicated by the referenceinformation into a parameter that has a same property as that of thestatus parameter, and then perform comparison. This is not limited inthis embodiment of this application either. For example, the terminaldevice learns the RI in the first CSI, and the reference information isused to indicate a threshold of the quantity of REs occupied by thesecond CSI on the uplink channel. In an implementation, the terminaldevice may calculate, based on the RI in the first CSI, the quantity ofREs occupied by the first CSI on the uplink channel, and then comparethe quantity of REs occupied by the first CSI on the uplink channel, asthe status parameter, with the threshold of the quantity of REs occupiedby the second CSI on the uplink channel. In another implementation, theterminal device may calculate a threshold of the RI of the second CSIbased on the threshold that is of the quantity of REs occupied by thesecond CSI on the uplink channel and that the reference information isused to indicate, and then compare the RI of the first CSI with thethreshold of the RI.

The CSI fed back by the terminal device to the network device usuallyincludes parameters such as a rank indication (RI), a precoding matrixindicator (PMI), and a channel quality indicator (CQI). An informationbit quantity of the PMI and an information bit quantity of the CQI maychange as the RI changes. Therefore, to ensure that both a maximumquantity of PMI bits and a maximum quantity of CQI bits can be carriedin the uplink channel together with the uplink data, the network devicemay always allocate a resource based on a maximum CSI bit quantity.However, the CSI reporting triggered by the network device may behigh-precision CSI reporting, and bit quantities of high-precision CSImay differ by one time with different RIs. If the network device alwaysallocates an uplink channel resource based on a maximum CSI bitquantity, the uplink channel resource is wasted.

Usually, to avoid waste of the uplink channel resource, the networkdevice may not allocate a resource based on a maximum CSI bit quantitycorresponding to an RI, but estimates, based on prior information, an RIreported by the terminal device. In this case, an uplink channelresource allocated by the network device to the terminal device isunnecessarily capable of satisfying an uplink channel resource needed bythe first CSI reported by the terminal device. Therefore, the terminaldevice needs to determine whether to discard some parameters in thefirst CSI. Likewise, the network device needs to learn whether theterminal device discards some parameters in the first CSI. In otherwords, the network device needs to determine whether the received secondCSI includes all parameters in the first CSI or includes some parametersin the first CSI. In view of this, a piece of reference information,namely, the foregoing reference information, is introduced in thisembodiment of this application. The terminal device may determine, basedon the reference information, whether some parameters in the first CSIneed to be discarded, and the network device may also performdetermining based on the reference information, to learn a bit quantityof the actually reported second CSI or a quantity of REs occupied on theuplink channel, so that behavior of the terminal device is controllableand predictable, and a situation in which a CSI transmission failureoccurs because understanding of the terminal device is inconsistent withthat of the network device.

According to the data transmission method in this embodiment of thisapplication, after determining, based on the reference information andthe CSI that needs to be reported and that is configured by the networkdevice for the terminal device, CSI that can be actually reported, theterminal device reports the CSI, so that the terminal device canproperly use a limited uplink channel resource allocated by the networkdevice to the terminal device, thereby improving transmissionperformance of the CSI.

Optionally, the first CSI may include an RI and a CQI. For the CQI inthe first CSI, the CQI may be a broadband CQI, in other words, a valueis calculated for a channel of the M subbands. Optionally, the CQI maybe a CQI of each of the M subbands, where the CQI of the subband iscalculated for a channel of the subband of the M subbands. Optionally,the CQI of the subband of the M subbands may be a differential valuecalculated relative to a broadband CQI, in other words, the CQI in thefirst CSI includes a broadband CQI and the CQI of the subband of the Msubbands. This is not limited in this embodiment of this application.

Optionally, the first CSI includes an RI, a CQI, and a PMI. The PMIincludes a broadband PMI and subband PMIs of the M subbands. Optionally,a CQI of each of the M subbands is calculated based on the RI, a firstPMI, and a PMI on the subband. A PMI of each subband may beindependently calculated, or PMIs of all subbands are dependentlycalculated. During independent calculation, the PMI of each subband maybe calculated based on a channel sounding result of the subband, and isunrelated to channel sounding results of other subbands. Duringdependent calculation, optionally, PMIs of some subbands are obtainedthrough joint processing such as an interpolation algorithm or a linearcombination algorithm based on PMIs of other subbands. This is notlimited in this embodiment of this application. Using the interpolationalgorithm as an example, the terminal device assumes that PMIs on somesubbands are obtained through the interpolation algorithm, to calculateCQIs on these subbands. An assumption based on which a PMI and/or a CQIof each subband is specifically calculated may be determined based on apredefined rule, based on an indication of the network device, or basedon comparison between at least one of the transmission parameter of theuplink data, the parameter in the first CSI (for example, the RI), andthe transmission parameter of the first CSI and the referenceinformation according to the method of this application. This is notlimited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicateat least one of a threshold of the rank indication (RI) and a thresholdof a transmission parameter of the second CSI, where the transmissionparameter of the second CSI includes at least one of the followingparameters: the quantity of resource elements (REs) occupied by thesecond CSI on the uplink channel, a quantity of modulation symbols ofthe second CSI, an information bit quantity of the second CSI, and a bitquantity of the second CSI after channel coding is performed.

Specifically, the reference information may indicate the threshold ofthe RI, may indicate a threshold of the quantity of REs occupied by thesecond CSI on the uplink channel, may indicate a threshold of thequantity of modulation symbols of the second CSI, may indicate athreshold of the information bit quantity of the second CSI (namely, abit quantity of the second CSI before encoding), and may also indicate athreshold of the bit quantity of the second CSI after channel coding isperformed.

It should be understood that, the foregoing indication may be a directindication or may be an indirect indication (which is a correspondingthreshold that can be derived by using a mapping relationship). This isnot limited in this embodiment of this application. For example, for thedirect indication, the reference information may directly be that thethreshold of the RI is 2. For the indirect indication, the referenceinformation may be a threshold identifier of the RI, and the terminaldevice may determine, based on the threshold identifier, that thethreshold of the RI is 2. All these situations shall fall within theprotection scope of the embodiments of this application.

In an optional embodiment, the reference information is used to indicatethe threshold of the RI, and the status parameter is the RI in the firstCSI; and if the RI in the first CSI is greater than the threshold of theRI, the second CSI includes some parameters in the first CSI, or if theRI in the first CSI is less than or equal to the threshold of the RI,the second CSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the threshold ofthe RI, and the terminal device may compare the RI in the first CSI withthe threshold of the RI. If the RI in the first CSI is greater than thethreshold of the RI, the terminal device may determine that the uplinkchannel resource configured by the network device is insufficient totransmit the first CSI, and some parameters in the first CSI need to bediscarded, in other words, the second CSI may include some parameters inthe first CSI; or if the RI in the first CSI is less than or equal tothe threshold of the RI, the terminal device may determine that theuplink channel resource configured by the network device is sufficientto transmit the first CSI, and the second CSI may include all parametersin the first CSI.

It should be understood that, because the second CSI includes allparameters or some parameters in the first CSI, the RI in the first CSIis the same as the RI in the second CSI in this embodiment of thisapplication. It should be further understood that, if the RI in thefirst CSI is equal to the threshold of the RI, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicatea first threshold of the quantity of REs occupied by the second CSI onthe uplink channel, and the status parameter is the quantity of REsoccupied by the first CSI on the uplink channel; and if the quantity ofREs occupied by the first CSI on the uplink channel is greater than thefirst threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the first CSI on the uplinkchannel is less than or equal to the first threshold, the second CSIincludes all parameters in the first CSI.

Specifically, the reference information may indicate the first thresholdof the quantity of REs occupied by the second CSI on the uplink channel,and the terminal device may compare the quantity of REs occupied by thefirst CSI on the uplink channel with the first threshold. If thequantity of REs occupied by the first CSI on the uplink channel isgreater than the first threshold, the terminal device may determine thatthe uplink channel resource configured by the network device isinsufficient to transmit the first CSI, and some parameters in the firstCSI need to be discarded, in other words, the second CSI may includesome parameters in the first CSI; or if the quantity of REs occupied bythe first CSI on the uplink channel is less than or equal to the firstthreshold, the terminal device may determine that the uplink channelresource configured by the network device is sufficient to transmit thefirst CSI, and the second CSI may include all parameters in the firstCSI.

It should be understood that, in another implementation, if the quantityof REs occupied by the first CSI on the uplink channel is greater thanor equal to the first threshold, it is determined that some parametersin the first CSI need to be discarded, or if the quantity of REsoccupied by the first CSI on the uplink channel is less than the firstthreshold, the second CSI includes all parameters in the first CSI.Subsequent embodiments are similar, and details are not described again.

It should be understood that, the terminal device may directly determinethe quantity of REs occupied by the first CSI on the uplink channel, ormay calculate, based on the RI in the first CSI, the quantity of REsoccupied by the first CSI on the uplink channel. It should be furtherunderstood that, if the quantity of REs occupied by the first CSI on theuplink channel is equal to the first threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicatea second threshold of the quantity of modulation symbols of the secondCSI, and the status parameter is the quantity of modulation symbols ofthe first CSI; and if the quantity of modulation symbols of the firstCSI is greater than the second threshold, the second CSI includes someparameters in the first CSI, or if the quantity of modulation symbols ofthe first CSI is less than or equal to the second threshold, the secondCSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the secondthreshold of the quantity of modulation symbols of the second CSI, andthe terminal device may compare the quantity of modulation symbols ofthe first CSI with the second threshold. If the quantity of modulationsymbols of the first CSI is greater than the second threshold, theterminal device may determine that the uplink channel resourceconfigured by the network device is insufficient to transmit the firstCSI, and some parameters in the first CSI need to be discarded, in otherwords, the second CSI may include some parameters in the first CSI; orif the quantity of modulation symbols of the first CSI is less than orequal to the second threshold, the terminal device may determine thatthe uplink channel resource configured by the network device issufficient to transmit the first CSI, and the second CSI may include allparameters in the first CST.

It should be understood that, the terminal device may directly determinethe quantity of modulation symbols of the first CSI, or may calculate,based on the RI in the first CSI, the quantity of modulation symbols ofthe first CSI. It should be further understood that, if the quantity ofmodulation symbols of the first CSI is equal to the second threshold,the second CSI may alternatively include some parameters in the firstCSI. This is not limited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicatea third threshold of the information bit quantity of the second CSI, andthe status parameter is the information bit quantity of the first CSI;and if the information bit quantity of the first CSI is greater than thethird threshold, the second CSI includes some parameters in the firstCSI, or if the information bit quantity of the first CSI is less than orequal to the third threshold, the second CSI includes all parameters inthe first CSI.

Specifically, the reference information may indicate the third thresholdof the information bit quantity of the second CSI, and the terminaldevice may compare the information bit quantity of the first CSI withthe third threshold. If the information bit quantity of the first CSI isgreater than the third threshold, the terminal device may determine thatthe uplink channel resource configured by the network device isinsufficient to transmit the first CSI, and some parameters in the firstCSI need to be discarded, in other words, the second CSI may includesome parameters in the first CSI; or if the information bit quantity ofthe first CSI is less than or equal to the third threshold, the terminaldevice may determine that the uplink channel resource configured by thenetwork device is sufficient to transmit the first CSI, and the secondCSI may include all parameters in the first CSI.

It should be understood that, the information bit quantity of the firstCSI is a bit quantity of the first CSI before channel coding isperformed. The terminal device may directly determine the informationbit quantity of the first CSI, or may calculate, based on the RI in thefirst CSI, the information bit quantity of the first CSI. It should befurther understood that, if the information bit quantity of the firstCSI is equal to the third threshold, the second CSI may alternativelyinclude some parameters in the first CSI. This is not limited in thisembodiment of this application.

In an optional embodiment, the reference information is used to indicatea fourth threshold of the bit quantity of the second CSI after channelcoding is performed, and the status parameter is the bit quantity of thefirst CSI after channel coding is performed; and if the bit quantity ofthe first CSI after channel coding is performed is greater than thefourth threshold, the second CSI includes some parameters in the firstCSI, or if the bit quantity of the first CSI after channel coding isperformed is less than or equal to the fourth threshold, the second CSIincludes all parameters in the first CSI.

Specifically, the reference information may indicate the fourththreshold of the bit quantity of the second CSI after channel coding isperformed, and the terminal device may compare the bit quantity of thefirst CSI after channel coding is performed with the fourth threshold.If the bit quantity of the first CSI after channel coding is performedis greater than the fourth threshold, the terminal device may determinethat the uplink channel resource configured by the network device isinsufficient to transmit the first CSI, and some parameters in the firstCSI need to be discarded, in other words, the second CSI may includesome parameters in the first CSI; or if the bit quantity of the firstCSI after channel coding is performed is less than or equal to thefourth threshold, the terminal device may determine that the uplinkchannel resource configured by the network device is sufficient totransmit the first CSI, and the second CSI may include all parameters inthe first CSI.

It should be understood that, the terminal device may directly determinethe bit quantity of the first CSI after channel coding is performed, ormay calculate, based on the RI in the first CSI, the bit quantity of thefirst CSI after channel coding is performed. It should be furtherunderstood that, if the bit quantity of the first CSI after channelcoding is performed is equal to the fourth threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

In an optional embodiment, the sending, by the terminal device, secondCSI includes: sending, by the terminal device, the second CSI and theuplink data, where the uplink data and the second CSI are carried on asame uplink channel.

Correspondingly, the network device receives the second CSI and theuplink data.

Specifically, the terminal device may add the second CSI to the uplinkchannel together with the uplink data and send the second CSI and theuplink data to the network device. In this case, the uplink channelresource allocated by the network device is shared by the second CSI andthe uplink data.

In a possible implementation, the terminal device receives resourceallocation information of the uplink channel, and MCS information of amodulation and coding scheme (MCS) code word of the uplink data by usingfirst signaling. When one code word is transmitted in the uplink data,the first signaling includes an MCS of one code word, or when two codewords are transmitted in the uplink data, the first signaling includesan MCS of two code words. The uplink channel is used to carry the secondCSI and the uplink data. Optionally, the first signaling may be DCIsignaling. The terminal device receives a parameter β by using secondsignaling, and the parameter P is used to determine a channel codingparameter of all or part of parameters of CSI carried on the uplinkchannel. For example, the parameter β may be used to determine a channelcoding parameter of a PMI, and may be used to determine a channel codingparameter of a CQI. Optionally, in the second signaling, same β ordifferent β may be set for an RI, a PMI, and a CQI. Optionally, thesecond signaling may be RRC signaling.

The terminal device may obtain information bits of the first CSI bymeasuring a reference signal, and obtain information bits of the uplinkdata from to-be-sent data. Based on the configuration of the networkdevice, the first CSI may include an RI, a PMI, and a CQI, may includeonly an RI and a PMI, or may include only an RI and a CQI. This is notlimited in this embodiment of this application. Only one PMI and one CQImay be fed back for entire bandwidth, or a PMI and/or a CQI of eachsubband may be fed back for the subband in entire bandwidth. Theterminal device determines, based on the first signaling and the secondsignaling, information about a first resource occupied by all or part ofparameters in the first CSI on the uplink channel, and/or a channelcoding parameter of all or part of parameters in the first CSI, forexample, a channel coding code rate of the first CSI.

The terminal device may determine, in a plurality of manners, theinformation about the first resource occupied by all or part ofparameters in the first CSI on the uplink channel. Optionally, theterminal device may determine, based on a ratio of an information bitquantity (which may include a CRC check bit) of each parameter in thefirst CSI to an information bit quantity (which may include a CRC checkbit) of to-be-sent data, values of the corresponding parameter, andresource allocation information included in the first signaling, aquantity of resource elements (REs) occupied by the parameter, in otherwords, determine information about a first resource occupied by theparameter. Optionally, if the terminal device performs joint channelcoding on a plurality of parameters in the first CSI, the terminaldevice may determine, based on a ratio of a total information bitquantity (which may include a CRC check bit) of the plurality ofparameters to an information bit quantity (which may include a CRC checkbit) of to-be-sent data, values of the corresponding parameters, andresource allocation information included in the first signaling, aquantity of REs jointly occupied by the plurality of parameters, inother words, determine information about a first resource occupied bythe plurality of parameters. This is not limited in this embodiment ofthis application. Then, the terminal device may determine, based on theinformation about the first resource and the resource allocationinformation, information about a second resource occupied by the uplinkdata on the uplink channel. The terminal device may determine a channelcoding parameter of the uplink data such as a channel coding code rateof the uplink data based on the information about the second resourceand the MCS information.

The terminal device may determine, based on all or part of informationof the information about the first resource, the information about thesecond resource, the channel coding parameter of the first CSI, and thechannel coding parameter of the uplink data and based on the referenceinformation, information actually carried on the uplink channel. Forexample, the terminal device may determine to add all or part of thefirst CSI to the uplink channel but not to add the uplink data, theterminal device determines to add all CSI and the uplink data to theuplink channel, or the terminal device determines to add part of thefirst CSI and the uplink data to the uplink channel. This is not limitedin this embodiment of this application.

The terminal device again determines, based on a parameter in the secondCSI that can be actually sent, a time-frequency resource occupied by thesecond CSI, and a channel coding parameter. The terminal device performschannel coding on the parameter in the second CSI, to obtain bits afterCSI encoding. Then, the terminal device modulates the bits after CSIencoding, to obtain a CSI modulation symbol. Finally, the terminaldevice maps the CSI modulation symbol to a CSI time-frequency resourcebased on the determined time-frequency resource. If the terminal devicealso sends the uplink data, the terminal device again determines, basedon the CSI time-frequency resource, the channel coding code rate of theuplink data and a time-frequency resource occupied by the uplink data,and performs channel coding on to-be-sent uplink data, to obtain bitsafter data encoding. Then, the terminal device modulates the bits afterdata encoding, to obtain a data modulation symbol. Finally, the terminaldevice modulates the data on a corresponding time-frequency resource.The terminal device sends the second CSI or sends the second CSI and theuplink data on the uplink channel.

In an optional embodiment, the transmission parameter of the second CSIfurther includes: a ratio of the quantity of REs occupied by the secondCSI on the uplink channel to a total quantity of REs included in theuplink channel.

In an optional embodiment, the reference information is used to indicatea fifth threshold of the ratio of the quantity of REs occupied by thesecond CSI on the uplink channel to the total quantity of REs includedin the uplink channel, and the status parameter is a ratio of thequantity of REs occupied by the first CSI on the uplink channel to thetotal quantity of REs included in the uplink channel; and if the ratioof the quantity of REs occupied by the first CSI on the uplink channelto the total quantity of REs included in the uplink channel is greaterthan the fifth threshold, the second CSI includes some parameters in thefirst CSI, or if the ratio of the quantity of REs occupied by the firstCSI on the uplink channel to the total quantity of REs included in theuplink channel is less than or equal to the fifth threshold, the secondCSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the fifth thresholdof the ratio of the quantity of REs occupied by the second CSI on theuplink channel to the total quantity of REs included in the uplinkchannel, and the terminal device may compare the ratio of the quantityof REs occupied by the first CSI on the uplink channel to the totalquantity of REs included in the uplink channel with the fifth threshold.If the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is greater than the fifth threshold, the terminal device maydetermine that the uplink channel resource configured by the networkdevice is insufficient to transmit the first CSI, and some parameters inthe first CSI need to be discarded, in other words, the second CSI mayinclude some parameters in the first CSI; or if the ratio of thequantity of REs occupied by the first CSI on the uplink channel to thetotal quantity of REs included in the uplink channel is less than orequal to the fifth threshold, the terminal device may determine that theuplink channel resource configured by the network device is sufficientto transmit the first CSI, and the second CSI may include all parametersin the first CSI.

It should be understood that, resource elements of the uplink channelmay be collectively referred to as a resource element set, and the ratioof the quantity of REs occupied by the first CSI on the uplink channelto the total quantity of REs included in the uplink channel may also bereferred to as a ratio of a quantity of REs of the first CSI in aresource element set to a total quantity of REs in the resource elementset. This is not limited in this embodiment of this application. Theterminal device may directly determine the ratio of the quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel, or may calculate, based on the RI inthe first CSI, the ratio of the quantity of REs occupied by the firstCSI on the uplink channel to the total quantity of REs included in theuplink channel. It should be further understood that, if the ratio ofthe quantity of REs occupied by the first CSI on the uplink channel tothe total quantity of REs included in the uplink channel is equal to thefifth threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application.

In an optional embodiment, the reference information is used to indicatea threshold of the transmission parameter of the uplink data; and thetransmission parameter of the uplink data includes at least one of thefollowing parameters: a channel coding code rate of the uplink data, aquantity of REs occupied by the uplink data on the uplink channel, aquantity of modulation symbols of the uplink data, and a ratio of thequantity of REs occupied by the uplink data on the uplink channel to atotal quantity of REs included in the uplink channel.

Specifically, when the network device schedules the terminal device tosend both the second CSI and the uplink data, the reference informationmay indicate the channel coding code rate of the uplink data, mayindicate the quantity of REs occupied by the uplink data on the uplinkchannel, may indicate the quantity of modulation symbols of the uplinkdata, or may indicate the ratio of the quantity of REs occupied by theuplink data on the uplink channel to the total quantity of REs includedin the uplink channel. This is not limited in this embodiment of thisapplication.

It should be understood that, the foregoing indication may be a directindication or may be an indirect indication (which is a correspondingthreshold that can be derived by using a mapping relationship). This isnot limited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicatea sixth threshold of the channel coding code rate of the uplink data,and the status parameter is the channel coding code rate of the uplinkdata; and if the channel coding code rate of the uplink data is greaterthan the sixth threshold, the second CSI includes some parameters in thefirst CSI, or if the channel coding code rate of the uplink data is lessthan or equal to the sixth threshold, the second CSI includes allparameters in the first CSI.

Specifically, the reference information may indicate the sixth thresholdof the channel coding code rate of the uplink data, and the terminaldevice may compare the channel coding code rate of the uplink data withthe sixth threshold. If the channel coding code rate of the uplink datais greater than the sixth threshold, the terminal device may determinethat the uplink channel resource configured by the network device isinsufficient to transmit the first CSI, and some parameters in the firstCSI need to be discarded, in other words, the second CSI may includesome parameters in the first CSI; or if the channel coding code rate ofthe uplink data is less than or equal to the sixth threshold, theterminal device may determine that the uplink channel resourceconfigured by the network device is sufficient to transmit the firstCSI, and the second CSI may include all parameters in the first CSI.

It should be understood that, the terminal device may calculate thechannel coding code rate of the uplink data based on resource allocationinformation and the parameters in the first CSI. It should be furtherunderstood that, if the channel coding code rate of the uplink data isequal to the sixth threshold, the second CSI may alternatively includesome parameters in the first CSI. This is not limited in this embodimentof this application.

In an optional embodiment, the reference information is used to indicatea seventh threshold of the quantity of REs occupied by the uplink dataon the uplink channel, and the status parameter is the quantity of REsoccupied by the uplink data on the uplink channel; and if the quantityof REs occupied by the uplink data on the uplink channel is less thanthe seventh threshold, the second CSI includes some parameters in thefirst CSI, or if the quantity of REs occupied by the uplink data on theuplink channel is greater than or equal to the seventh threshold, thesecond CSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the sevenththreshold of the quantity of REs occupied by the uplink data on theuplink channel, and the terminal device may compare the quantity of REsoccupied by the uplink data on the uplink channel with the sevenththreshold. If the quantity of REs occupied by the uplink data on theuplink channel is greater than the seventh threshold, the terminaldevice may determine that the uplink channel resource configured by thenetwork device is insufficient to transmit the first CSI, and someparameters in the first CSI need to be discarded, in other words, thesecond CSI may include some parameters in the first CSI; or if thequantity of REs occupied by the uplink data on the uplink channel isless than or equal to the seventh threshold, the terminal device maydetermine that the uplink channel resource configured by the networkdevice is sufficient to transmit the first CSI, and the second CSI mayinclude all parameters in the first CSI.

It should be understood that, the terminal device may calculate, basedon the resource allocation information and the parameters in the firstCSI, the quantity of REs occupied by the uplink data on the uplinkchannel. It should be further understood that, if the quantity of REsoccupied by the uplink data on the uplink channel is equal to theseventh threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application.

In an optional embodiment, the reference information is used to indicatean eighth threshold of the quantity of modulation symbols of the uplinkdata, and the status parameter is the quantity of modulation symbols ofthe uplink data and if the quantity of modulation symbols of the uplinkdata is less than the eighth threshold, the second CSI includes someparameters in the first CSI, or if the quantity of modulation symbols ofthe uplink data is greater than or equal to the eighth threshold, thesecond CSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the eighththreshold of the quantity of modulation symbols of the uplink data, andthe terminal device may compare the quantity of modulation symbols ofthe uplink data with the eighth threshold. If the quantity of modulationsymbols of the uplink data is greater than the eighth threshold, theterminal device may determine that the uplink channel resourceconfigured by the network device is insufficient to transmit the firstCSI, and some parameters in the first CSI need to be discarded, in otherwords, the second CSI may include some parameters in the first CST; orif the quantity of modulation symbols of the uplink data is less than orequal to the eighth threshold, the terminal device may determine thatthe uplink channel resource configured by the network device issufficient to transmit the first CSI, and the second CSI may include allparameters in the first CSI.

It should be understood that, the terminal device may calculate thequantity of modulation symbols of the uplink data based on the resourceallocation information and the parameters in the first CSI. It should befurther understood that, if the quantity of modulation symbols of theuplink data is equal to the eighth threshold, the second CSI mayalternatively include some parameters in the first CSI. This is notlimited in this embodiment of this application.

In an optional embodiment, the reference information is used to indicatea ninth threshold of the ratio of the quantity of REs occupied by theuplink data on the uplink channel to the total quantity of REs includedin the uplink channel, and the status parameter is the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel; and if the ratioof the quantity of REs occupied by the uplink data on the uplink channelto the total quantity of REs included in the uplink channel is less thanthe ninth threshold, the second CSI includes some parameters in thefirst CSI, or if the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel is greater than or equal to the ninth threshold, thesecond CSI includes all parameters in the first CSI.

Specifically, the reference information may indicate the ninth thresholdof the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel, and the terminal device may compare the ratio of the quantityof REs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel with the ninth threshold.If the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel is greater than the ninth threshold, the terminal device maydetermine that the uplink channel resource configured by the networkdevice is insufficient to transmit the first CSI, and some parameters inthe first CSI need to be discarded, in other words, the second CSI mayinclude some parameters in the first CSI; or if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is less than orequal to the ninth threshold, the terminal device may determine that theuplink channel resource configured by the network device is sufficientto transmit the first CSI, and the second CSI may include all parametersin the first CSI.

It should be understood that, the terminal device may calculate, basedon the resource allocation information and the parameters in the firstCSI, the ratio of the quantity of REs occupied by the uplink data on theuplink channel to the total quantity of REs included in the uplinkchannel. It should be further understood that, if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is equal to theninth threshold, the second CSI may alternatively include someparameters in the first CSI. This is not limited in this embodiment ofthis application.

It should be further understood that, the reference information mayindicate one or more thresholds. If the reference information indicatesa plurality of thresholds, there may be the following two situations:

1. The reference information indicates a threshold of each of aplurality of status parameters.

Specifically, the reference information may indicate more than one ofthe following thresholds: the threshold of the RI, the first thresholdof the quantity of resource elements (REs) occupied by the second CSI onthe uplink channel, the second threshold of the quantity of modulationsymbols of the second CSI, the third threshold of the information bitquantity of the second CSI, the fourth threshold of the bit quantity ofthe second CSI after channel coding is performed, the fifth threshold ofthe ratio of the quantity of REs occupied by the second CSI on theuplink channel to the total quantity of REs included in the uplinkchannel, the sixth threshold of the channel coding code rate of theuplink data, the seventh threshold of the quantity of REs occupied bythe uplink data on the uplink channel, the eighth threshold of thequantity of modulation symbols of the uplink data, and the ninththreshold of the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel. The terminal device may determine to report allparameters of the first CSI when the status parameter of the first CSIsatisfies a determining condition of any one of a plurality ofthresholds indicated by the reference information, or may determine toreport all parameters of the first CSI when the status parameter of thefirst CSI satisfies determining conditions of all thresholds indicatedby the reference information; otherwise, the terminal device reportssome parameters in the first CSI. This is not limited in this embodimentof this application.

2. The reference information indicates a plurality of thresholds of astatus parameter.

Specifically, the reference information may indicate a plurality ofthresholds such as two thresholds for a status parameter.

Using an example in which the status parameter is the channel codingcode rate of the uplink data, the reference information indicatesthresholds r1 and r2 of the channel coding code rate of the uplink data.When the channel coding code rate of the uplink data is greater than r1but is less than r2, the terminal device may report some parameters inthe first CSI and all of the uplink data; when the channel coding coderate of the uplink data is greater than r2, the terminal device mayreport all or part of parameters in the first CSI, but does not reportthe uplink data, where if the terminal device determines that the uplinkchannel may carry all of the first CSI, the terminal device reports allparameters in the first CSI, or if the terminal device determines thatthe uplink channel is insufficient to carry all of the first CSI, theterminal device reports some parameters in the first CSI; or when thechannel coding code rate of the uplink data is less than r1, theterminal device may report all parameters in the first CSI and theuplink data.

Using an example in which the status parameter is the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel, the referenceinformation indicates thresholds p1 and p2 of the ratio of the quantityof REs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel. When the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is less than p1 butis greater than p2, the terminal device may report some parameters inthe first CSI and all of the uplink data; when the ratio of the quantityof REs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel is less than p2 but isgreater than 0, the terminal device reports all parameters in the firstCSI but does not report the uplink data; otherwise, the uplink channelis insufficient to carry all of the CSI, and the terminal device reportssome parameters in the first CSI; or when the ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel is greater than p1, theterminal device reports all parameters of the first CSI and the uplinkdata.

It should be understood that, in this embodiment of this application,because the first CSI needs to be transmitted on the uplink channeltogether with the uplink data, a sum of the quantity of REs occupied bythe first CSI on the uplink channel and the quantity of REs occupied bythe uplink data on the uplink channel should be equal to the totalquantity of REs included in the uplink channel. For example, the totalquantity of REs included in the uplink channel is 100. In this case, ifthe threshold p2 is equal to ½, and a quantity of REs that the CSI needsto occupy is 75, a ratio is 75/100=3/4, which is less than p2 and isgreater than 0. In this case, the terminal device reports all parametersin the first CSI, but does not report the uplink data. If a quantity ofREs that the first CSI needs to occupy is 125, the total quantity of REsincluded in the uplink channel are insufficient to transmit the CSI, andmoreover there is no RE that may send the uplink data. Therefore, theterminal device reports only some parameters in the first CSI.

Using an example in which the status parameter is the ratio of thequantity of REs occupied by the first CSI on the uplink channel to thetotal quantity of REs included in the uplink channel, the referenceinformation indicates thresholds q1 and q2 of the ratio of the quantityof REs occupied by the second CSI on the uplink channel to the totalquantity of REs included in the uplink channel. When the ratio of thequantity of REs occupied by the first CSI on the uplink channel to thetotal quantity of REs included in the uplink channel is greater than q1but is less than q2, the terminal device reports some parameters in thefirst CSI and all of the uplink data according to the foregoing rule;when the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is greater than q2 but is less than 1, the terminal devicereports all parameters in the first CSI but does not report the uplinkdata; when the ratio of the quantity of REs occupied by the first CSI onthe uplink channel to the total quantity of REs included in the uplinkchannel is greater than 1, the terminal device reports some parametersin the first CSI; or when the ratio of the quantity of REs occupied bythe first CSI on the uplink channel to the total quantity of REsincluded in the uplink channel is less than q1, the terminal devicereports all parameters in the first CSI and the uplink data.

It should be understood that, the foregoing description is only adescription example, and a situation in which the status parameter isanother parameter and has two thresholds is similar to the foregoingsituations. Details are not described herein again.

In this embodiment of this application, if the terminal devicedetermines the second CSI by comparing the parameter in the first CSIwith the reference information, for example, the parameter in the firstCSI is the RI and the reference information is the threshold of the RI,the terminal device reports PMIs of some subbands, CQIs of all subbands,and the RI when the RI exceeds the threshold of the RI. Optionally, inthis case, in the CQIs of all of the subbands, a subband PMI that is notreported is calculated according to the foregoing interpolation methodwith reference to an obtained subband PMI. When the RI does not exceedthe threshold of the RI, the terminal device reports PMIs of all of thesubbands, the CQIs of all of the subbands, and the RI. Optionally, inthis case, when the terminal device calculates the CQIs of all of thesubbands, the terminal device assumes that the PMIs of these subbandsare calculated independently according to the foregoing interpolationmethod, and unless a default rule is used, CQIs of some subbands arecalculated based on a PMI determined according to the interpolationmethod.

Likewise, if the terminal device determines the second CSI by comparingthe transmission parameter of the uplink data with the referenceinformation, for example, the transmission parameter of the uplink datais the channel coding code rate of the uplink data and the referenceinformation is the threshold of the channel coding code rate of theuplink data, the terminal device reports PMIs of some subbands, CQIs ofall subbands, and the RI when the channel coding code rate of the uplinkdata exceeds the threshold of the channel coding code rate of the uplinkdata. Optionally, in this case, in the CQIs of all of the subbands, asubband PMI that is not reported is calculated according to theforegoing interpolation method with reference to an obtained subbandPMI. When the channel coding code rate of the uplink data does notexceed the threshold of the channel coding code rate of the uplink data,the terminal device reports PMIs of all of the subbands, the CQIs of allof the subbands, and the RI. Optionally, in this case, when the terminaldevice calculates the CQIs of all of the subbands, the terminal deviceassumes that the PMIs of these subbands are calculated independentlyaccording to the foregoing interpolation method, and unless a defaultrule is used, CQIs of some subbands are calculated based on a PMIdetermined according to the interpolation method.

A situation in which the reference information is another parameter suchas the quantity of resource elements (REs) occupied by the second CSI onthe uplink channel, the quantity of modulation symbols of the secondCSI, the information bit quantity of the second CSI, the bit quantity ofthe second CSI after channel coding is performed, the quantity of REsoccupied by the uplink data on the uplink channel, the quantity ofmodulation symbols of the uplink data, and the ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel is similar to theforegoing situations. Details are not described herein again.

In an optional embodiment, before the sending, by the terminal device,second CSI, the method further includes, determining, by the terminaldevice based on the comparison result and priority information, whetherto send the uplink data, where the priority information is used toindicate priorities of the second CSI and the uplink data; and thesending, by the terminal device, second CSI includes: sending, by theterminal device, the second CSI and the uplink data if the terminaldevice determines to send the uplink data.

Specifically, the terminal device may first determine priorities of CSIand the uplink data based on the priority information, and thendetermine whether the uplink data needs to be sent, in other words,determine, based on the priority information, to preferably discard someinformation in the first CSI or preferably discard the uplink data. Thefollowing two situations are specifically used as an example fordescription.

The reference information is the quantity of REs occupied by the firstCSI on the uplink channel. If a CSI priority is higher, when thequantity of REs occupied by the first CSI on the uplink channel exceedsthe first threshold, but is less than a quantity of REs included in atime-frequency resource of the uplink channel allocated in the firstsignaling (for example, DCI), the terminal device reports the second CSIbut does not report the uplink data, and the second CSI may include allparameters in the first CSI; or when the quantity of REs occupied by thefirst CSI on the uplink channel exceeds a quantity of REs included in atime-frequency resource of the uplink channel, the terminal devicereports the second CSI, and the second CSI is a proper subset of thefirst CSI. If a priority of the uplink data is higher, when the quantityof REs occupied by the first CSI exceeds the first threshold, theterminal device reports the second CSI and the uplink data, and thesecond CSI includes some parameters in the first CSI.

The reference information is the ratio of the quantity of REs occupiedby the uplink data on the uplink channel to the total quantity of REsincluded in the uplink channel. If the CSI priority is higher, when theratio of the quantity of REs occupied by the uplink data on the uplinkchannel to the total quantity of REs included in the uplink channel isgreater than the ninth threshold but is greater than 0, the terminaldevice reports the second CSI but does not report the uplink data, andthe second CSI includes the first CSI; or when the ratio of the quantityof REs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel is less than 0, theterminal device reports the second CSI, and the second CSI includes someparameters in the first CSI. If the priority of the uplink data ishigher, when the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel is less than the ninth threshold, the terminal devicereports the second CSI and the uplink data, and the second CSI includessome parameters in the first CSI.

It should be understood that, the priority information may bepredefined, or may be configured by the network device for the terminaldevice by using signaling. This is not limited in this embodiment ofthis application.

In an optional embodiment, the parameter in the first CSI includes:second frequency domain granularity parameters of M subbands and a firstfrequency domain granularity parameter, where the first frequency domaingranularity parameter includes an RI, and the second frequency domaingranularity parameters of the M subbands include a channel qualityindicator (CQI) of each of the M subbands and/or a precoding matrixindicator (PMI) of the subband; and the parameter in the second CSIincludes any one of the following: second frequency domain granularityparameters of N subbands and the first frequency domain granularityparameter; all or part of second frequency domain granularity parametersof each of the M subbands and the first frequency domain granularityparameter; and the first frequency domain granularity parameter, the CQIof each of the M subbands, and a PMI of each of the N subbands, wherethe M subbands include the N subbands, both M and N are integers greaterthan or equal to 1, and M is greater than N.

It should be understood that, the first frequency domain granularityparameter is also referred to as a broadband parameter and has a samevalue on the M subbands, and the second frequency domain granularityparameter is also referred to as a subband parameter and has a differentvalue for each of the M subbands. Specifically, if the second CSIreported by the terminal device includes some parameters in the firstCSI, the terminal device may select some parameters in the first CSIbased on a predefined rule to perform reporting. For example, theterminal device may report only a proportion of parameters (for example,an RI, a broadband PMI, all subband CQIs, and a proportion of subbandPMIs; an RI, a broadband PMI, and a proportion of subband PMIs andsubband CQIs; an RI, a broadband PMI, a broadband CQI, a subband PMIand/or a subband CQI of the M subbands whose indices are the highest; oran RI, and PMIs and/or CQIs corresponding to some DFT vectors) in thefirst CSI based on a default rule.

Optionally, the terminal device may determine a proportion, the terminaldevice reports a proportion of CSI parameters and the uplink data, andthe proportion may ensure that the data and the second CSI can becarried on the uplink channel. For example, if a predefined proportionis ½, the terminal device may report the RI, CQIs of all of the Msubbands, the broadband PMI, and subband PMIs of M/2 subbands. In TypeII codebook design (namely, high-precision CSI reporting) of new radio(NR), an information bit quantity of a PMI corresponding to RI=2 isapproximately equal to twofold an information bit quantity of a PMIcorresponding to RI=1. Therefore, when the network device assumes thatthe terminal device is to report CSI corresponding to RI=1 and allocatea time-frequency resource of the uplink channel based on RI=1, theterminal device reports some parameters in the first CSI based on aproportion of ½, to ensure that the resource of the uplink channelallocated by the network device to the terminal device is sufficient tocarry the second CSI (namely, some parameters in the first CSI).

Optionally, the terminal device may determine n proportions x_(i), where0≤x_(i)≤1, i=1, . . . , n, n is an integer greater than 1, and x_(i)indicates that the terminal device may discard subband parameters (forexample, a subband CQI and/or a subband PMI) of M×x_(i) subbands basedon the proportions x_(i), or the terminal device may report a broadbandparameter and subband parameters (for example, a subband CQI and/or asubband PMI) of M×x_(i) subbands based on the proportions x_(i). Duringspecific implementation, when a threshold indicated by the referenceinformation is satisfied, the terminal device may discard as few aspossible parameters, in other words, report as many as possibleparameters. It is assumed that there are three proportions: x₁, x₂, andx₃, the reference information is the threshold of the RI, an upper boundof a CSI bit quantity corresponding to the threshold of the RI is A, anda bit quantity corresponding to the first CSI is B. Using the case inwhich the terminal device may discard the subband parameters of theM×x_(i) subbands based on the proportions x_(i) as an example, theterminal device may select a minimum x_(i) from the foregoing threeproportions, so that B× (1−x_(i))<A. In other words, subband parametersof M× x_(i) subbands are discarded, and remaining parameters in thefirst CSI that are used as the second CSI are carried on the uplinkchannel and sent. Using the case in which the terminal device may reportthe broadband parameter and the subband parameters of the M×x_(i)subbands based on the proportions x_(i) as an example, the terminaldevice may select a maximum x_(i) from the foregoing three proportions,so that B×x_(i)<A. In other words, subband parameters of M× x_(i)subbands are reported.

It should be understood that, the foregoing proportions may bepredefined, or may be configured by the network device for the terminaldevice by using signaling. This is not limited in this embodiment ofthis application. In this way, when determining that the second CSIreported by the terminal device is some parameters in the first CSI, thenetwork device may directly determine, based on the foregoingproportions, subbands whose parameters are discarded by the terminaldevice, and subbands whose parameters are reported by the terminaldevice.

In an optional embodiment, the reference information is predefined; orthe method further includes: sending, by the network device, thereference information to the terminal device by using signaling; andcorrespondingly, receiving, by the terminal device, the referenceinformation sent by the network device.

In an optional embodiment, the signaling is any one of the followingsignaling: radio resource control RRC signaling, downlink controlinformation (DCI) signaling, and a Media Access Control control element(MAC CE) signaling.

Specifically, the signaling that is used to carry the referenceinformation and that is sent by the network device to the terminaldevice may be radio resource control (RRC) signaling, may be downlinkcontrol information (DCI), or may be Media Access Control (MAC) layercontrol element (CE) signaling. This is not limited in this embodimentof this application.

It should be understood that, using the RRC signaling to configure thereference information is applicable to a scenario in which theconfiguration of the reference information does not frequently changeand is relatively stable, and bit overheads of signaling of a physicallaver and a MAC layer may be greatly reduced. Using the DCI to configurethe reference information helps the terminal device perform fastdetection, to ensure that the terminal device receives the referenceinformation in a timely manner. However, using the MAC CE signaling toconfigure the reference information is applicable to a scenario in whichthe reference information changes relatively dynamically. A decodingspeed of the MAC CE signaling is higher than that of the RRC signaling.Therefore, in such a scenario, the network device uses the MAC CEsignaling to configure the reference information more efficiently.

It should be understood that, sequence numbers of the foregoingprocesses do not indicate an execution sequence, and an executionsequence of the processes shall be determined based on functions andinternal logic thereof, and shall constitute no limitation on animplementation process of the embodiments of this application.

The data transmission method according to the embodiments of thisapplication is described in detail above with reference to FIG. 1 andFIG. 2 , and a terminal device and a network device according to theembodiments of this application are described in detail below withreference to FIG. 3 to FIG. 6 .

FIG. 3 shows a terminal device 300 provided in an embodiment of thisapplication. The terminal device 300 includes: a determining unit 310and a transceiver unit 320.

The determining unit 310 is configured to determine referenceinformation, and the transceiver unit 320 is configured to send secondchannel state information (CSI) based on a comparison result of thereference information and a status parameter, where the second CSIincludes all parameters in first CSI or includes some parameters in thefirst CSI, the first CSI is CSI that needs to be reported and that isconfigured by a network device for the terminal device, and the statusparameter includes at least one of a transmission parameter of uplinkdata, a parameter in the first CSI, and a transmission parameter of thefirst CSI.

In this embodiment of this application, after determining, based on thereference information and the CSI that needs to be reported and that isconfigured by the network device for the terminal device, CSI that canbe actually reported, the terminal device reports the CSI, so that theterminal device can properly use a limited uplink channel resourceallocated by the network device to the terminal device, therebyimproving transmission performance of the CSI.

Optionally, the reference information is used to indicate at least oneof a threshold of a rank indication (RI) and a threshold of atransmission parameter of the second CSI, where the transmissionparameter of the second CSI includes at least one of the followingparameters: a quantity of resource elements (REs) occupied by the secondCSI on an uplink channel, a quantity of modulation symbols of the secondCSI, an information bit quantity of the second CSI, and a bit quantityof the second CSI after channel coding is performed.

Optionally, the reference information is used to indicate the thresholdof the RI, and the status parameter is an RI in the first CSI; and ifthe RI in the first CSI is greater than the threshold of the RI, thesecond CSI includes some parameters in the first CSI, or if the RI inthe first CSI is less than or equal to the threshold of the RI, thesecond CSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate a firstthreshold of the quantity of REs occupied by the second CSI on theuplink channel, and the status parameter is a quantity of REs occupiedby the first CSI on the uplink channel; and if the quantity of REsoccupied by the first CSI on the uplink channel is greater than thefirst threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the first CSI on the uplinkchannel is less than or equal to the first threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a secondthreshold of the quantity of modulation symbols of the second CSI, andthe status parameter is a quantity of modulation symbols of the firstCSI; and if the quantity of modulation symbols of the first CSI isgreater than the second threshold, the second CSI includes someparameters in the first CSI, or if the quantity of modulation symbols ofthe first CSI is less than or equal to the second threshold, the secondCSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate a thirdthreshold of the information bit quantity of the second CSI, and thestatus parameter is an information bit quantity of the first CSI; and ifthe information bit quantity of the first CSI is greater than the thirdthreshold, the second CSI includes some parameters in the first CSI, orif the information bit quantity of the first CSI is less than or equalto the third threshold, the second CSI includes all parameters in thefirst CSI.

Optionally, the reference information is used to indicate a fourththreshold of the bit quantity of the second CSI after channel coding isperformed, and the status parameter is a bit quantity of the first CSIafter channel coding is performed; and if the bit quantity of the firstCSI after channel coding is performed is greater than the fourththreshold, the second CSI includes some parameters in the first CSI, orif the bit quantity of the first CSI after channel coding is performedis less than or equal to the fourth threshold, the second CSI includesall parameters in the first CSI.

Optionally, the transceiver unit 320 is specifically configured to: sendthe second CSI and the uplink data, where the uplink data and the secondCSI are carried on a same uplink channel.

Optionally, the transmission parameter of the second CSI furtherincludes: a ratio of the quantity of REs occupied by the second CSI onthe uplink channel to a total quantity of REs included in the uplinkchannel.

Optionally, the reference information is used to indicate a fifththreshold of the ratio of the quantity of REs occupied by the second CSIon the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is a ratio of a quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel; and if the ratio of the quantity ofREs occupied by the first CSI on the uplink channel to the totalquantity of REs included in the uplink channel is greater than the fifththreshold, the second CSI includes some parameters in the first CSI, orif the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is less than or equal to the fifth threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a threshold ofthe transmission parameter of the uplink data; and the transmissionparameter of the uplink data includes at least one of the followingparameters: a channel coding code rate of the uplink data, a quantity ofREs occupied by the uplink data on the uplink channel, a quantity ofmodulation symbols of the uplink data, and a ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel.

Optionally, the reference information is used to indicate a sixththreshold of the channel coding code rate of the uplink data, and thestatus parameter is the channel coding code rate of the uplink data; andif the channel coding code rate of the uplink data is greater than thesixth threshold, the second CSI includes some parameters in the firstCSI, or if the channel coding code rate of the uplink data is less thanor equal to the sixth threshold, the second CSI includes all parametersin the first CSI.

Optionally, the reference information is used to indicate a sevenththreshold of the quantity of REs occupied by the uplink data on theuplink channel, and the status parameter is the quantity of REs occupiedby the uplink data on the uplink channel; and if the quantity of REsoccupied by the uplink data on the uplink channel is less than theseventh threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the uplink data on the uplinkchannel is greater than or equal to the seventh threshold, the secondCSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate an eighththreshold of the quantity of modulation symbols of the uplink data, andthe status parameter is the quantity of modulation symbols of the uplinkdata; and if the quantity of modulation symbols of the uplink data isless than the eighth threshold, the second CSI includes some parametersin the first CSI, or if the quantity of modulation symbols of the uplinkdata is greater than or equal to the eighth threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a ninththreshold of the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is the ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel; and if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is less than theninth threshold, the second CSI includes some parameters in the firstCSI, or if the ratio of the quantity of REs occupied by the uplink dataon the uplink channel to the total quantity of REs included in theuplink channel is greater than or equal to the ninth threshold, thesecond CSI includes all parameters in the first CSI.

Optionally, the determining unit 310 is further configured to: beforethe second CSI is sent, determine, based on the comparison result andpriority information, whether the uplink data is to be sent, where thepriority information is used to indicate priorities of the second CSIand the uplink data; and the transceiver unit 320 is specificallyconfigured to: send the second CSI and the uplink data if it isdetermined that the uplink data is to be sent.

Optionally, the parameter in the first CSI includes: second frequencydomain granularity parameters of M subbands and a first frequency domaingranularity parameter, where the first frequency domain granularityparameter includes an RI, and the second frequency domain granularityparameters of the M subbands include a channel quality indicator (CQI)of each of the M subbands and/or a precoding matrix indicator (PMI) ofthe subband; and a parameter in the second CSI includes any one of thefollowing: second frequency domain granularity parameters of N subbandsand the first frequency domain granularity parameter; all or part ofsecond frequency domain granularity parameters of each of the M subbandsand the first frequency domain granularity parameter; and the firstfrequency domain granularity parameter, the CQI of each of the Msubbands, and a PMI of each of the N subbands, where the M subbandsinclude the N subbands, both M and N are integers greater than or equalto 1, and M is greater than N.

Optionally, the reference information is predefined, or the referenceinformation is configured by the network device for the terminal deviceby using signaling.

Optionally, the signaling is any one of the following signaling: radioresource control RRC signaling, downlink control information (DCI)signaling, and a Media Access Control control element (MAC CE)signaling.

It should be understood that, the terminal device 300 herein is embodiedin a form of a functional unit. The term “unit” herein may be anapplication-specific integrated circuit (ASIC), an electronic circuit, aprocessor (for example, a shared processor, a dedicated processor, or agroup processor) configured to execute one or more software or firmwareprograms, a memory, a merging logic circuit, and/or another appropriatecomponent supporting the described function. In an optional example, aperson skilled in the art may understand that, the terminal device 300may be specifically the terminal device in the foregoing embodiment, andthe terminal device 300 may be configured to perform procedures and/orsteps corresponding to the terminal device in the foregoing methodembodiment. To avoid repetition, details are not described herein again.

FIG. 4 shows a network device 400 provided in an embodiment of thisapplication. The network device 400 includes: a transceiver unit 410 anda determining unit 420.

The transceiver unit 410 is configured to receive a rank indication (RI)in second CSI; and the determining unit 420 is configured to determine,based on a comparison result obtained by comparing a status parameterwith reference information, at least one of a bit quantity of the secondCSI and a quantity of resource elements (REs) occupied by the second CSIon an uplink channel, where the status parameter is determined based onthe RI, the status parameter includes at least one of a transmissionparameter of uplink data, a parameter in first CSI, and a transmissionparameter of the first CSI, the first CSI is CSI that needs to bereported and that is configured by the network device for a terminaldevice, and the second CSI includes all parameters in the first CSI orincludes some parameters in the first CSI.

In this embodiment of this application, the network device receives thesecond CSI reported by the terminal device, and the second CSI isreported after the terminal device determines, based on the referenceinformation and the CSI that needs to be reported and that is configuredby the network device for the terminal device, CSI that can be actuallyreported, so that the terminal device can properly use a limited uplinkchannel resource allocated by the network device to the terminal device,thereby improving transmission performance of the CSI.

Optionally, the reference information is used to indicate at least oneof a threshold of the rank indication (RI) of the second CSI and athreshold of a transmission parameter of the second CSI, where thetransmission parameter of the second CSI includes at least one of thefollowing parameters: the quantity of resource elements (REs) occupiedby the second CSI on the uplink channel, a quantity of modulationsymbols of the second CSI, an information bit quantity of the secondCSI, and a bit quantity of the second CSI after channel coding isperformed.

Optionally, the reference information is used to indicate the thresholdof the RI, and the status parameter is the RI; and if the RI is greaterthan the threshold of the RI, the second CSI includes some parameters inthe first CSI; or if the RI is less than or equal to the threshold ofthe RI, the second CSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate a firstthreshold of the quantity of REs occupied by the second CSI on theuplink channel, and the status parameter is a quantity of REs occupiedby the first CSI on the uplink channel; and if the quantity of REsoccupied by the first CSI on the uplink channel is greater than thefirst threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the first CSI on the uplinkchannel is less than or equal to the first threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a secondthreshold of the quantity of modulation symbols of the second CSI, andthe status parameter is a quantity of modulation symbols of the firstCSI; and if the quantity of modulation symbols of the first CSI isgreater than the second threshold, the second CSI includes someparameters in the first CSI, or if the quantity of modulation symbols ofthe first CSI is less than or equal to the second threshold, the secondCSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate a thirdthreshold of the information bit quantity of the second CSI, and thestatus parameter is an information bit quantity of the first CSI; and ifthe information bit quantity of the first CSI is greater than the thirdthreshold, the second CSI includes some parameters in the first CSI, orif the information bit quantity of the first CSI is less than or equalto the third threshold, the second CSI includes all parameters in thefirst CSI.

Optionally, the reference information is used to indicate a fourththreshold of the bit quantity of the second CSI after channel coding isperformed, and the status parameter is a bit quantity of the first CSIafter channel coding is performed; and if the bit quantity of the firstCSI after channel coding is performed is greater than the fourththreshold, the second CSI includes some parameters in the first CSI, orif the bit quantity of the first CSI after channel coding is performedis less than or equal to the fourth threshold, the second CSI includesall parameters in the first CSI.

Optionally, the transceiver unit 410 is specifically configured to:receive the second CSI and the uplink data, where the uplink data andthe second CSI are carried on a same uplink channel.

Optionally, the transmission parameter of the second CSI furtherincludes: a ratio of the quantity of REs occupied by the second CSI onthe uplink channel to a total quantity of REs included in the uplinkchannel.

Optionally, the reference information is used to indicate a fifththreshold of the ratio of the quantity of REs occupied by the second CSIon the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is a ratio of a quantity of REsoccupied by the first CSI on the uplink channel to the total quantity ofREs included in the uplink channel; and if the ratio of the quantity ofREs occupied by the first CSI on the uplink channel to the totalquantity of REs included in the uplink channel is greater than the fifththreshold, the second CSI includes some parameters in the first CSI, orif the ratio of the quantity of REs occupied by the first CSI on theuplink channel to the total quantity of REs included in the uplinkchannel is less than or equal to the fifth threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a threshold ofthe transmission parameter of the uplink data; and the transmissionparameter of the uplink data includes at least one of the followingparameters: a channel coding code rate of the uplink data, a quantity ofREs occupied by the uplink data on the uplink channel, a quantity ofmodulation symbols of the uplink data, and a ratio of the quantity ofREs occupied by the uplink data on the uplink channel to a totalquantity of REs included in the uplink channel.

Optionally, the reference information is used to indicate a sixththreshold of the channel coding code rate of the uplink data, and thestatus parameter is the channel coding code rate of the uplink data; andif the channel coding code rate of the uplink data is greater than thesixth threshold, the second CSI includes some parameters in the firstCSI, or if the channel coding code rate of the uplink data is less thanor equal to the sixth threshold, the second CSI includes all parametersin the first CSI.

Optionally, the reference information is used to indicate a sevenththreshold of the quantity of REs occupied by the uplink data on theuplink channel, and the status parameter is the quantity of REs occupiedby the uplink data on the uplink channel; and if the quantity of REsoccupied by the uplink data on the uplink channel is less than theseventh threshold, the second CSI includes some parameters in the firstCSI, or if the quantity of REs occupied by the uplink data on the uplinkchannel is greater than or equal to the seventh threshold, the secondCSI includes all parameters in the first CSI.

Optionally, the reference information is used to indicate an eighththreshold of the quantity of modulation symbols of the uplink data, andthe status parameter is the quantity of modulation symbols of the uplinkdata; and if the quantity of modulation symbols of the uplink data isless than the eighth threshold, the second CSI includes some parametersin the first CSI, or if the quantity of modulation symbols of the uplinkdata is greater than or equal to the eighth threshold, the second CSIincludes all parameters in the first CSI.

Optionally, the reference information is used to indicate a ninththreshold of the ratio of the quantity of REs occupied by the uplinkdata on the uplink channel to the total quantity of REs included in theuplink channel, and the status parameter is the ratio of the quantity ofREs occupied by the uplink data on the uplink channel to the totalquantity of REs included in the uplink channel; and if the ratio of thequantity of REs occupied by the uplink data on the uplink channel to thetotal quantity of REs included in the uplink channel is less than theninth threshold, the second CSI includes some parameters in the firstCSI, or if the ratio of the quantity of REs occupied by the uplink dataon the uplink channel to the total quantity of REs included in theuplink channel is greater than or equal to the ninth threshold, thesecond CSI includes all parameters in the first CSI.

Optionally, the parameter in the first CSI includes: second frequencydomain granularity parameters of M subbands and a first frequency domaingranularity parameter, where the first frequency domain granularityparameter includes an RI, and the second frequency domain granularityparameters of the M subbands include a channel quality indicator (CQI)of each of the M subbands and/or a precoding matrix indicator (PMI) ofthe subband; and a parameter in the second CSI includes any one of thefollowing: second frequency domain granularity parameters of N subbandsand the first frequency domain granularity parameter; all or part ofsecond frequency domain granularity parameters of each of the M subbandsand the first frequency domain granularity parameter; and the firstfrequency domain granularity parameter, the CQI of each of the Msubbands, and a PMI of each of the N subbands, where the M subbandsinclude the N subbands, both M and N are integers greater than or equalto 1, and M is greater than N.

Optionally, the reference information is predefined, or the transceiverunit 410 is further configured to: send the reference information to theterminal device by using signaling.

Optionally, the signaling is any one of the following signaling: radioresource control RRC signaling, downlink control information (DCI)signaling, and a Media Access Control control element (MAC CE)signaling.

It should be understood that, the network device 400 herein is embodiedin a form of a functional unit. The term “unit” herein may be anapplication-specific integrated circuit (ASIC), an electronic circuit, aprocessor (for example, a shared processor, a dedicated processor, or agroup processor) configured to execute one or more software or firmwareprograms, a memory, a merging logic circuit, and/or another appropriatecomponent supporting the described function. In an optional example, aperson skilled in the art may understand that, the network device 400may be specifically the network device in the foregoing embodiment, andthe network device 400 may be configured to perform procedures and/orsteps corresponding to the network device in the foregoing methodembodiment. To avoid repetition, details are not described herein again.

FIG. 5 shows another network device 500 provided in an embodiment ofthis application. The network device 500 includes a processor 510 and atransceiver 520, and optionally, the network device 500 may furtherinclude a memory 530. The processor 510, the transceiver 520, and thememory 530 communicate with each other by using an internal connectionpath, the memory 530 is configured to store an instruction, and theprocessor 510 is configured to execute the instruction stored in thememory 530, so as to control the transceiver 520 to send a signal and/orreceive a signal.

When the program instruction stored in the memory 530 is executed by theprocessor 510, the processor 510 is configured to receive a rankindication (RI) in second CSI by using the transceiver 520; anddetermine, based on a comparison result obtained by comparing the statusparameter with the reference information, at least one of a bit quantityof the second CSI and a quantity of resource elements (REs) occupied bythe second CSI on an uplink channel, where the status parameter isdetermined based on the RI, the status parameter includes at least oneof a transmission parameter of uplink data, a parameter in first CSI,and a transmission parameter of the first CSI, the first CSI is CSI thatneeds to be reported and that is configured by the network device for aterminal device, and the second CSI includes all parameters in the firstCSI or includes some parameters in the first CSI.

The processor 510 and the memory 530 may be combined into a processingapparatus, and the processor 510 is configured to execute program codestored in the memory 530 to implement the foregoing function. Duringspecific implementation, the memory 530 may be integrated in theprocessor 510, or may be independent of the processor 510.

The network device 500 may further include an antenna 540, configured tosend, by using a radio signal, downlink data or downlink controlsignaling output by the transceiver 520. It should be understood that,the network device 500 may be specifically the network device in thedata transmission method 200, and may be configured to perform stepsand/or procedures corresponding to the network device in the datatransmission method 200. Optionally, the memory 530 may include aread-only memory and a random access memory, and provide an instructionand data for the processor. A part of the memory may further include anon-volatile random access memory. For example, the memory may furtherstore information about a device type. The processor 510 may beconfigured to execute the instruction stored in the memory, and when theprocessor 510 executes the instruction stored in the memory, theprocessor 510 is configured to perform steps and/or procedures of themethod embodiment corresponding to the network device.

FIG. 6 shows another terminal device 600 provided in an embodiment ofthis application. As shown in FIG. 6 , the terminal device 600 includesa processor 601 and a transceiver 602, and optionally, the terminaldevice 600 further includes a memory 603. The processor 601, thetransceiver 602, and the memory 603 communicate with each other by usingan internal connection path, to transfer a control signal and/or a datasignal, the memory 603 is configured to store a computer program, andthe processor 601 is configured to invoke the computer program from thememory 603 and run the computer program, so as to control thetransceiver 602 to receive/transmit a signal.

When a program instruction stored in the memory 603 is executed by theprocessor 601, the processor 601 is configured to determine referenceinformation; and send, by using the transceiver 602, second channelstate information (CSI) based on a comparison result of the referenceinformation and a status parameter, where the second CSI includes allparameters in first CSI or includes some parameters in the first CSI,the first CSI is CSI that needs to be reported and that is configured bya network device for the terminal device, and the status parameterincludes at least one of a transmission parameter of uplink data, aparameter in the first CSI, and a transmission parameter of the firstCSI.

The processor 601 and the memory 603 may be combined into a processingapparatus, and the processor 601 is configured to execute program codestored in the memory 603 to implement the foregoing function. Duringspecific implementation, the memory 603 may be integrated in theprocessor 601, or may be independent of the processor 601. The terminaldevice 600 may further include an antenna 604, configured to send, byusing a radio signal, uplink data or uplink control signaling output bythe transceiver 602.

It should be understood that, the terminal device 600 may bespecifically the terminal device in the data transmission method 200,and may be configured to perform steps and/or procedures correspondingto the terminal device in the data transmission method 200. Optionally,the memory 630 may include a read-only memory and a random accessmemory, and provide an instruction and data for the processor. A part ofthe memory may further include a non-volatile random access memory. Forexample, the memory may further store information about a device type.The processor 601 may be configured to execute the instruction stored inthe memory, and when the processor 601 executes the instruction storedin the memory, the processor 601 is configured to perform steps and/orprocedures of the method embodiment corresponding to the terminaldevice.

The processor 601 may be configured to perform an action that isinternally implemented by a terminal and that is described in theforegoing method embodiment, and the transceiver 602 may be configuredto perform an action of transmission or sending that is performed by theterminal to the terminal device and that is described in the foregoingmethod embodiment. For details, refer to the description in theforegoing method embodiment. Details are not described herein again.

The terminal device 600 may further include a power supply 606,configured to supply power to various devices or circuits in theterminal device 600.

In addition, to improve functions of the terminal device, the terminaldevice 600 may further include one or more of an input unit 606, adisplay unit 607, an audio frequency circuit 608, a camera 609, a sensor610, and the like, and the audio frequency circuit may further include aspeaker 6082, a microphone 6084, and the like.

It should be understood that in the embodiments of this application, theprocessor in the network device 500 and the terminal device 600 may be acentral processing unit (CPU), or the processor may be another generalpurpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field programmablegate array (FPGA) or another programmable logic device, a discrete gateor transistor logic device, a discrete hardware component, or the like.The general purpose processor may be a microprocessor, or the processormay be any conventional processor or the like.

In an implementation process, steps in the foregoing methods may beimplemented by using a hardware integrated logic circuit in theprocessor, or by using an instruction in a form of software. The stepsof the methods disclosed with reference to the embodiments of thisapplication may be directly performed by a hardware processor, or may beperformed by using a combination of hardware in the processor and asoftware unit. The software unit may be located in a mature storagemedium in the art, such as a random access memory, a flash memory, aread-only memory, a programmable read-only memory, an electricallyerasable programmable memory, or a register. The storage medium islocated in the memory, and the processor reads an instruction in thememory and performs the steps in the foregoing methods in combinationwith hardware of the processor. To avoid repetition, details are notdescribed herein again.

It should be understood that, the term “and/or” in this specificationdescribes only an association relationship for describing associatedobjects and represents that three relationships may exist. For example,A and/or B may represent the following three cases: Only A exists, bothA and B exist, and only B exists. In addition, the character “/” in thisspecification generally indicates an “or” relationship between theassociated objects.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, method steps and units may be implemented by electronichardware, computer software, or a combination thereof. To clearlydescribe the interchangeability between the hardware and the software,the foregoing has generally described steps and compositions of eachembodiment based on functions. Whether the functions are performed byhardware or software depends on particular applications and designconstraint conditions of the technical solutions. A person of ordinaryskill in the art may use different methods to implement the describedfunctions for each particular application, but it should not beconsidered that the implementation goes beyond the scope of thisapplication.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, refer to acorresponding process in the foregoing method embodiments, and detailsare not described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the shown or discussed mutualcouplings or direct couplings or communication connections may beimplemented through some interfaces, indirect couplings or communicationconnections between the apparatuses or units, or electrical connections,mechanical connections, or connections in other forms.

The units described as separate parts may or may not be physicallyseparate, and parts shown as units may or may not be physical units, maybe located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected depending onactual requirements to achieve the objectives of the solutions of theembodiments in this application.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units may be integrated into one unit.The integrated unit may be implemented in a form of hardware, or may beimplemented in a form of a software functional unit.

When the integrated unit is implemented in the form of a softwarefunctional unit and sold or used as an independent product, theintegrated unit may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of thisapplication essentially, or the part contributing to the prior art, orall or part of the technical solutions may be implemented in a form of asoftware product. The computer software product is stored in a storagemedium and includes several instructions for instructing a computerdevice (which may be a personal computer, a server, a network device, orthe like) to perform all or part of the steps of the methods describedin the embodiments of this application. The foregoing storage mediumincludes any medium that can store program code, such as a USB flashdrive, a removable hard disk, a read-only memory (ROM), a random accessmemory (RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific embodiments of thisapplication, but are not intended to limit the protection scope of thisapplication. Any modification or replacement readily figured out by aperson skilled in the art within the technical scope disclosed in thisapplication shall fall within the protection scope of this application.Therefore, the protection scope of this application shall be subject tothe protection scope of the claims.

1. A data transmission method, comprising: receiving, by a terminaldevice, radio resource control (RRC) signaling from a network device;determining, by the terminal device based on reference informationcomprised in the RRC signaling, a threshold of a quantity of modulationsymbols for carrying channel state information (CSI) of a bandwidth parton a physical uplink shared channel (PUSCH); and sending, by theterminal device, all or a portion of parameters in CSI configured by thenetwork device to be reported for the bandwidth part, based on acomparison result of a quantity of modulation symbols for carrying theCSI configured by the network device to be reported for the bandwidthpart and the threshold.
 2. The method according to claim 1, whereinsending all or a portion of the parameters in the CSI comprises sendingthe portion of the parameters in the CSI in response to determining thatthe quantity of modulation symbols for carrying the CSI is greater thanthe threshold.
 3. The method according to claim 2, wherein the portionof the parameters in the CSI is absent of subband pre-coding matrixindicators (PMIs) corresponding to a proportion of subbands of thebandwidth part.
 4. The method according to claim 2, wherein the portionof the parameters in the CSI comprises: wideband PMI, subband PMIscorresponding to a proportion of subbands of the bandwidth part, andchannel quality indicators (CQIs) corresponding to all subbands of thebandwidth part.
 5. A data transmission method, comprising: sending, by anetwork device to a terminal device, radio resource control (RRC)signaling that comprises reference information for determining athreshold of a quantity of modulation symbols for carrying channel stateinformation (CSI) of bandwidth part on a physical shared channel(PUSCH); and determining, by the network device, all or a portion ofparameters in CSI configured by the network device to be reported forthe bandwidth part are reported, based on a comparison result of aquantity of modulation symbols for carrying the CSI configured by thenetwork device to be reported for the bandwidth part and the threshold.6. The method according to claim 5, wherein sending all or a portion ofthe parameters in the CSI comprises sending the portion of theparameters in the CSI in response to determining that the quantity ofmodulation symbols for carrying the CSI is greater than the threshold.7. The method according to claim 6, wherein the portion of theparameters in the CSI is absent of subband pre-coding matrix indicators(PMIs) corresponding to a proportion of subbands of the bandwidth part.8. The method according to claim 6, wherein the portion of theparameters in the CSI comprises: wideband PMI, subband PMIscorresponding to a proportion of subbands of the bandwidth part andchannel quality indicators (CQIs) corresponding to all subbands of thebandwidth part.
 9. A processing apparatus, comprising: at least oneprocessor; and one or more memories coupled to the at least oneprocessor and storing programming instructions for execution by the atleast one processor to: receive, radio resource control (RRC) signalingfrom a network device; determine, based on reference informationcomprised in the RRC signaling, a threshold of a quantity of modulationsymbols for carrying channel state information (CSI) of a bandwidth parton a physical uplink shared channel (PUSCH); and send, all or a portionof parameters in CSI configured by the network device to be reported forthe bandwidth part, based on a comparison result of a quantity ofmodulation symbols for carrying the CSI configured by the network deviceto be reported for the bandwidth part and the threshold.
 10. Theprocessing apparatus according to claim 9, wherein sending all or aportion of the parameters in the CSI comprises sending the portion ofthe parameters in the CSI in response to determining that the quantityof modulation symbols for carrying the CSI is greater than thethreshold.
 11. The processing apparatus according to claim 10, whereinthe portion of the parameters in the CSI is absent of subband pre-codingmatrix indicators (PMIs) corresponding to a proportion of subbands ofthe bandwidth part.
 12. The processing apparatus according to claim 10,wherein the portion of the parameters in the CSI comprises: widebandPMI, subband PMIs corresponding to a proportion of subbands of thebandwidth part and channel quality indicators (CQIs) corresponding toall subbands of the bandwidth part.
 13. A processing apparatus,comprising: at least one processor; and one or more memories coupled tothe at least one processor and storing programming instructions forexecution by the at least one processor to: send, to a terminal device,radio resource control (RRC) signaling that comprises referenceinformation for determining a threshold of a quantity of modulationsymbols for carrying channel state information (CSI) of bandwidth parton a physical shared channel (PUSCH); and determine, all or a portion ofparameters in CSI configured by the network device to be reported forthe bandwidth part are reported, based on a comparison result of aquantity of modulation symbols for carrying the CSI configured by thenetwork device to be reported for the bandwidth part and the threshold.14. The processing apparatus according to claim 13, wherein sending allor a portion of the parameters in the CSI comprises sending the portionof the parameters in the CSI in response to determining that thequantity of modulation symbols for carrying the CSI is greater than thethreshold.
 15. The processing apparatus according to claim 14, whereinthe portion of the parameters in the CSI is absent of subband pre-codingmatrix indicators (PMIs) corresponding to a proportion of subbands ofthe bandwidth part.
 16. The processing apparatus according to claim 14,wherein the portion of the parameters in the CSI comprises: widebandPMI, subband PMIs corresponding to a proportion of subbands of thebandwidth part and channel quality indicators (CQIs) corresponding toall subbands of the bandwidth part.